I hear you, it's really tough when the exhaustion hits like that, especially when you're managing high blood pressure at the same time. The back pain and tiredness are pretty common at this stage, but the fainting spells are something you should definitely flag with your doctor or PD soon, just to make sure everything's okay with your blood pressure and iron levels. In the meantime, try to rest whenever you can, even short naps help, and don't push yourself too hard at work if possible. You're almost at the third trimester, so hang in there, but definitely get that checked out first.