22 weeks pregnant!Need Advice?

Every single time after I eat I feel dizzy,excessive thirst and without strength I have to lay down for at least an hour or until I am feeling better, I am currently 22 weeks pregnant, i feel like my ob isn’t listening to me and says it’s pregnancy related or blames it on my anxiety but I just feel like something isn’t right, I did have gestational diabetes my last pregnancy but I don’t know could be that or something else, should I go to the birthing center or what do I do I cant live like this feeling like I’m gonna pass out every time I eat especially breakfast!, I’ve talked to my doctor about this but he says he tested me at 16 weeks and I passed my 3 hour test and won’t test me for another 2 weeks now, but besides that doesn’t want to send blood work to see if anything else is going on?? What do I do??