Paul said specifically that all feast days ARE shadows. There is plenty of information on the web about what these days signify.
Here are some references I found helpful when reserarching them:
Feast Days of the God of Israel
And this "anti-semitism" charge against the early church really wears thin after a while. The fact is the early church did not observe all these Jewish feast days because they were just that, purely Jewish feast days limited to the times and places of national Israel.
As celebrated by Jews, yes. As celebrated by Christians, no. And the anti-semitism of the early church is well documented and is a historical fact. I'm sorry if you believe otherwise.
Take "passover" for example, apart from eating the bread and drinking the cup that is commanded in keeping of the Lord's Supper, what do you do on your "passover" that is commanded in the Bible?
The biblical commandments of Christ are these:
Luk 22:19 And he took bread, and gave thanks, and brake [it], and gave unto them, saying, This is my body which is given for you: this do in remembrance of me.
Luk 22:20 Likewise also the cup after supper, saying, This cup [is] the new testament in my blood, which is shed for you.
Paul clarifies how they (the bread and wine) are to be taken:
1Co 11:27 Wherefore whosoever shall eat this bread, and drink [this] cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord.
1Co 11:28 But let a man examine himself, and so let him eat of [that] bread, and drink of [that] cup.
1Co 11:29 For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord's body.
Christ also specifically instructed his disciples to perform another rite on Passover, the day he died:
Joh 13:14 If I then, [your] Lord and Master, have washed your feet; ye also ought to wash one another's feet.
Joh 13:15 For I have given you an example, that ye should do as I have done to you.
The biblical commandments of Christ are these:
What you have described is the Lord's Supper, not passover. It's obvious that even you know that passover was a mere shadow, a tpe of Christ, that has passed away with the old covenant.