37 Weeks Pregnant, Have Severe Fatigue, Shortness Of Breath, Dizzy Spells. What Could Be Causing This?

Hello, I am 37 weeks and 5 days and lately I have been experiencing alot of fatigue , shortness of breath, and dizzy spells, I spoke with my doctor who advised me that it is probably because of my activity and movement, but I do not do too much, I only go to school 2 days out the week and the rest of my time is spent at home preparing for the baby to come. And the thing is it happens even when I m not active, like when I m on the couch or lying down I ll get swept with the fatigue and then I ll see like the little things they call stars as if i m going to faint, I just would like a second opinion as to what it could be because it keeps getting worse. Thank You