A couple of fun facts here. The Veronese Sacramentary is an old liturgical book that was compiled sometime between 558 and 600 AD. At least some of the prayers are attributed to Pope Leo the Great, so that's kind of neat.
The full passage from St. Ignatius, chapter 7, reads:
For some are in the habit of carrying about the name [of Jesus Christ] in wicked guile, while yet they practise things unworthy of God, whom you must flee as you would wild beasts. For they are ravening dogs, who bite secretly, against whom you must be on your guard, inasmuch as they are men who can scarcely be cured. There is one Physician who is possessed both of flesh and spirit; both made and not made; God existing in flesh; true life in death; both of Mary and of God; first passible and then impassible— even Jesus Christ our Lord.
Maybe the conciliar citation is wrong because the reference to "medicine" is in Chapter 20:
Especially [will I do this ] if the Lord make known to me that you come together man by man in common through grace, individually, in one faith, and in Jesus Christ, who was of the seed of David according to the flesh, being both the Son of man and the Son of God, so that you obey the bishop and the presbytery with an undivided mind, breaking one and the same bread, which is the medicine of immortality, and the antidote to prevent us from dying, but [which causes] that we should live for ever in Jesus Christ.
And forasmuch as, in this divine sacrifice which is celebrated in the mass, that same Christ is contained and immolated in an unbloody manner, who once offered Himself in a bloody manner on the altar of the cross; the holy Synod teaches, that this sacrifice is truly propritiatory and that by means thereof this is effected, that we obtain mercy, and find grace in seasonable aid, if we draw nigh unto God, contrite and penitent, with a sincere heart and upright faith, with fear and reverence. For the Lord, appeased by the oblation thereof, and granting the grace and gift of penitence, forgives even heinous crimes and sins. For the victim is one and the same, the same now offering by the ministry of priests, who then offered Himself on the cross, the manner alone of offering being different. The fruits indeed of which oblation, of that bloody one to wit, are received most plentifully through this unbloody one; so far is this (latter) from derogating in any way from that (former oblation). Wherefore, not only for the sins, punishments, satisfactions, and other necessities of the faithful who are living, but also for those who are departed in Christ, and who are not as yet fully purified, is it rightly offered, agreebly to a tradition of the apostles.
Show this to a too-large percentage of Catholics these days, and they'd probably wonder where you pulled such archaic, unenlightened language from. The Mass is a sacrifice. Not only is it a sacrifice, it is THE sacrifice. The only difference is the manner of the offering. And you can even have an offering for someone in purgatory.
Before He came to the river, while many people were running together to John to be baptized, he says to them, I indeed baptize you with water; but He that comes after me is greater than I, the latchet of whose shoes I am not worthy to loose; the same shall baptize you with the Holy Ghost, and with fire. Already he knew this also. What then did he learn from the dove, that he may not afterwards be found a liar (which God forbid we should think), if it be not this, that there was to be a certain peculiarity in Christ, such that, although many ministers, be they righteous or unrighteous, should baptize, the virtue of baptism would be attributed to Him alone on whom the dove descended, and of whom it was said, This is He that baptizes with the Holy Ghost? Peter may baptize, but this is He that baptizes; Paul may baptize, yet this is He that baptizes; Judas may baptize, still this is He that baptizes.
Valuable lessons for those who would let scandal bring them to doubt the sacraments.
Rightly, then, the liturgy is considered as an exercise of the priestly office of Jesus Christ. In the liturgy the sanctification of the man is signified by signs perceptible to the senses, and is effected in a way which corresponds with each of these signs; in the liturgy the whole public worship is performed by the Mystical Body of Jesus Christ, that is, by the Head and His members.
Which reminds me of something that has always bothered me. I hear a lot about how the pre-conciliar era was one dominated by clericalism and how the liturgy wasn't how the people wanted it. Does it not seem commonplace, though, that now the liturgy is dominated by a committee of people who ostracize those who do not share the clique's views on what a Mass should look like? Yeah, it happens.
From this it follows that every liturgical celebration, because it is an action of Christ the priest and of His Body which is the Church, is a sacred action surpassing all others; no other action of the Church can equal its efficacy by the same title and to the same degree.
Which brings us back to something that we have forgotten. Nothing you do will ever be more important than the sacraments. So, yes, you should try to show up for them. Even moreso, if you don't show up, they are still important. The Sacrifice does what God wants whether 5 people show up or 5000. The Mass is greater than receiving communion.