Don't know if I should be concerned?

So this whole weekend (4 days now) I have been feeling very weak and slightly dizzy. I'm 35 weeks pregnant as of today and I keep getting really hot and tired and it feels like something is pinching my neck then I feel like I am sedated and I can barely move my arms and legs out of pure exhaustion that came from out of nowhere. I also feel completely out of breath with every little thing that I do. I've had a super easy pregnancy so far. I haven't had any swelling l, no BP issues literately picture perfect health and I have only gained 5lbs after losing 20 off the get go. I called the dr yesterday and she said just to try and take it easy and take some Tylenol and I should feel better. I did that and I seemed to be ok and went to bed but now today it's the same story. Idk what to do. I don't want to keep calling and bothering her but is this really normal?? I'm a FTM so I really have no clue what "normal" is supposed to be like.