This is usally typical around this stage. If you have already spoken to a doctor and all your levels are good, keep on resting. Your big day is coming soon rest while you still can :) as long as you are still eating properly, take advantage and rest whenever you feel the need too
Is your iron low try iron pills they work for me but youre in the third trimester and my midwife said youay start feeling some of the syntoms you had in the first trimester