I think anyone who is remotely fit/active feels this way. The good news is the feeling passes, in about 9 months. Ba Dum.

When I was pregnant I just listened to my body. Some days were better/harder/faster/longer than others. I really had to rein in my expectations.

As for the hot yoga - I'd talk to your doctor, but I don't think overheating your body is very good for you. What exactly "overheating" looks like is another matter. I hate being too warm, so it was never an issue/consideration for me.

Good luck!