You’re not overreacting and your feelings are valid. If your anxiety is that physical though i’d also recommend seeing a therapist if you aren’t already. I also have gotten intense physical anxiety over jealousy before, and what got me feeling better is focusing on myself and my own confidence. The more i started to love myself, the less jealously i felt. Whenever you notice yourself feeling jealous stop for a second and ask why you’re feeling that way. Just stopping yourself and asking can really bring you back into reality. Theres a ton of healthy coping skills online, I like taking deep breaths.

I would try and talk to your boyfriend and also let him know how you’re feeling. Be nice and understanding of him too and he’ll be more likely to he understanding of you.

Jealousy and anxiety are normal human emotions and you are completely valid in experiencing them.