u/Dramatic_Response_20

I (37F) recently hired a trainer to help advance my strength training routine. I push myself hard, always have, and started out decently fit although with lower muscle mass than I'd like. I also have low body fat for a female at about 17%. I am 5'6.5" and usually about 114lbs. I have trained professionally in classical ballet, and I do HIIT, yoga, and home workouts routinely. My day to day is generally active.
Twice now, after hard strength training gym sessions, I end up having full body sweats, horrid nausea and then puking. It's disgusting and clearly not conducive to my fitness goals. What could be going on here?