Why Am I Having Panic Attacks During Intercourse?

Every few months I will have a string of panic attacks while I’m having sex with my boyfriend…They are bad, I can’t breath, my throat closes up, I cry hysterically, and I shake really bad. For some reason it always ends up also that I will skip my period that month then once this is all done I will go another 3-5 months being perfectly normal then they will strike again…can someone help?!