If my mother was born and raised jewish but became catholic to marry my dad does that make me jewish?

You have Jewish blood, yeah but these days we can identify as anything we like lol
They've done tests to see if its a race or a religion and all Jewish people have common genetic links that non Jewish people do not have

Nope

by nazi extermination standards, it would. for Israeli citizenship standards it would (they're the same, oddly), but as far as most people's view, I don't think so.

You would need to be raised Jewish. However if you converted to Judaism I suspect you may be more acceptable because your mother is Jewish. Just speculation here.

By Jewish law you are.
Judaism goes by the mother.
If she was born Jewish she is considered Jewish even if identifies with another religion.

According to Jewish tradition, yes. According to the HMC, no. Everyone else, it's just a matter of how you define yourself I think.

I have never before heard of someone converting from Judaism to Catholic

Not according to Jews.

What do you want to be?

But you still have the Jewish heritage and that is so special.

Nope, you choose what you believe to be true

You're still ethnically Jewish, because Jewish ancestry is traced through the mum's side.