Sex makes me feel ill

Recently lost my virginity to a girl who is sort of my fwb now. After my first time, I threw up, I put it down to just first time nerves but literally every time we have sex I feel the urge to puke. She’s a really attractive girl, hygienic and clean. Her breath doesn’t smell or anything but literally right after I finish I always have to rush off to the bathroom in case I vomit.

I only told her the first couple times, i’ve been keeping it from her now in case she thinks it’s because of her. I’m no longer nervous about having sex so I don’t think it’s that. It’s making me want to stop, which I don’t because it’s fun but if I can’t fuck without vomiting, it doesn’t seem worth it long term. I’ve been to a doctor who doesn’t believe it’s a physical reaction but rather a mental one. I have an appointment with a therapist and I can’t lie I’m scared shitless as to what she might say.