Anxiety about getting pregnant

My boyfriend and I are turning 20 this year. I am on birth control. But my boyfriend apparently gets very bad anxiety whenever we have sex still. He’s scared of accidentally getting me pregnant. I tell him let’s not have sex so he can just chill out a bit. I get frustrated with his anxiety about it because he constantly wants me to take pregnancy tests, but still doesn’t believe them if they come out negative. I bought some cheap tests off amazon because he had me taking them so much and i dont want to keep wasting $20 on first response.

I told him many times that if he is that scared, then let’s not have sex until we’re in a position where he would be okay with it. He doesn’t want to do that. And I will refuse once in a while cause I get annoyed of the anxiety. He gets upset when I refuse for that reason. I’m very small, so all I can use are the pills. I tried the IUD and the patch before but the doses were too high and caused my own anxiety (caused by other issues, not the same as his) to skyrocket. Panic attacks 24/7 and not sleeping a lot (sometimes no sleep, others 3-4 hours a night). So i had to quit both of those forms immediately.

The thing is, I’ve been 30lbs underweight for as long as I can remember and I don’t have my period off of birth control so I also think I’m infertile anyway due to that and a rape when I was a little younger. I’ve tried explaining that to him but he doesn’t understand as he’s not as educated. I dont know what to do because the anxiety is kind of draining me but he just gets upset if I refuse because of that. Any advice what I should do?