does this happens usually after you trying to crunch out that extra few reps, or trying to reach pr, by holding your breath in so hard until your face turn red and head shaking ?

if this is the case, you need to learn proper breathing technique, and lift calm, or just lower the weight altogether until you can handle it

if that is not the case, then im not really sure whats happening there, could be lack of some nutrition, electrolyte or something else

could it also be the weather, sometimes when the weather is too hot, and you didnt do enough warmup, straight go into working sets, will have migraine