It's not just you. Once I hit 27 weeks I all of a sudden started feeling that way. I have to push myself to clean the damn house even. So much to do and so little energy or motivation.

From what I understand, this is your welcome to be the third trimester. I'll be 28 weeks on Thursday and I posted about how different I've been feeling the last few days. Seems it's pretty common around 27-29 weeks to suddenly feel heavy, exhausted, uncomfortable and just different. Some people say after a week or two they felt a little better. There's a big hormone shift around 28 weeks also. Goodluck, I hope you feel better soon!