In the first weeks I was sleeping all the time and felt lethargic. Even now at 39+ weeks I'm still exhausted. I got up this morning at 10, had breakfast and went back to bed, then woke at around 1.30pm, had lunch, went back to sleep until 5.30pm when I had to get ready to meet friends for dinner.
Everyone is different and just because the books or internet sites say you should be feeling more energetic at a certain time in pregnancy, it doesn't mean you will. Apparently, I should have been sexually rampant in my second trimester, but I still have no interest.