Weak sauce 😔

I seriously cannot get enough sleep today! I've been in bed all day! It's already 5 pm and I'm still sleepy and exhausted and bleh.. I'm sitting on the toilet trying to get energy to get up and wipe but I can't even do that 😳 I don't remember feeling this exhausted at 33 weeks with my last 2.. I've been drinking water every chance I get cause I feel a little dehydrated.. you guys think it's just the heat? Or is this normal at 8 months?