I have has issues with dizziness and fainting during my pregnancy and it's getting worse each day. I was induced around 39 weeks with my previous pregnancy for same thing but it wasn't this bad. I was wondering if this time we should do it earlier at 38 weeks and if I should just do an induction or asked to have the Dr sweep my membranes to try to start labor on its own? I'm not sure what seems safest. Or if I should try to wait for natural labor while running the risk of injuring baby due to the fainting?

This is something you really should discuss with your doctor. No one on this site knows your medical history, your doctor does, so he/she is the one to talk to about this.