BCAA and Nausea?

For the last few weeks I have been feeling like complete shit in the gym. I have had what feels like phlegm in my throat and sinuses that starts not too long after I drink my pre-workout BCAA’s and doesn’t go away, and throughout my workout I progressively feel more nauseous (and sometimes have been throwing up near the ends of my workouts).

I have always drank two large spoonfuls BCAA’s pre/during/post-workout (2 PRE, 2 SIP ON DURING, 2 POST), but I thought maybe they could be the problem since lately I seem to feel sick after I drink them.

Anyway, today I didn’t use them, and I felt completely fine. So I believe it has to be the BCAA’s, even though I drank a small dose with my PWO shake and I don’t feel bad…

Does anybody know why this could be? Am I going overboard with the BCAA’s and triggering an allergic reaction? Or maybe I got a bad batch?

edit: My next off day I am going to drink a large amount of them during a sitting and see what happens to make sure it’s not something else… though I am pretty certain it isn’t.

I remember this happening to me when due to time constraints I drank my shake (with BCAAs) during my workout, as opposed to after. Although I tried it again a couple of times, and it doesn’t happen consistently. I’m interested to see how drinking it on your off day goes.

don’t eat/drink anything (except water) close to the beginning and during your workout

if that isn’t the problem then the only other issue i can think of might be some food sensitivity