Need Help Dealing With Overconfident Lab Partner. I Have Anxiety:(?

Forget about them. Truly, if I were you, I would email the professor right now. I would briefly explain your issues (uncooperative disrespectful partners). I would then request new partners. If that's impossible, then just do your best. One lab grade will not affect your over-all grade that much. And remember, your grade in this cl doesn't define who you are anyway. Best wishes.