extreme weakness

I'm 30 weeks and today I've noticed my arms feel so heavy and weak like I've been holding weights in my arms all day. I'll just be sitting down eating food or something and I have to rest. My heart pounds and I just need to take a break from whatever I'm doing. It also happens to my legs when I'm standing like brushing my teeth or doing makeup. Anyone else experience this? I'd talk to my doctor but I have no OB right now because I switched doctors and I'm still waiting for them to get my records from the first doctor. It's been over 2 weeks since I switched and I called today to check on progress and they still have nothing