Anyone else?

Dizzy/lightheaded during sex? Been happening since 20wks, 28wks now. not to be tmi, but it happens in every position, & doctors aren’t really sure why. I can say that im anemic & have low end of normal BP. I stay hydrated, no blood sugar issues, and have had neurological & cardiology tests ran - all normal. It also happens during showers, even when they’re not hot. I just bought a shower chair to help so i don’t feel as anxious. Is anyone else experiencing this or have experienced it before? It also happened in my first pregnancy and started at the same time, was gone PP. really just looking for some insights or any other mommas that are going through this as well.