I don't mean to get you down, but I'm at 28 weeks and I'm still tired most of the time. I never got that 2nd trimester energy burst my mother told me about. All my tests came back normal, I eat a LOT of clean protein, clean carbs, and drink lots of water. I think it has a lot to do with the fact that I don't exercise as much as I could/should (I find good vigorous exercise usually energized me), but also, all pregnancies are different. If you're tired all the time, listen to your body and sleep (while you still can!).
I work full-time in an office and there's a section of the office here that's completely unoccuppied by any staff. Sometimes, I disappear during lunch hour, take my winter coat with me and go sleep on the floor of one of the empty offices. It's not super comfy but I find that even a quick 20 minute lay-down, with my eye closed and my body relaxed makes a big difference in the rest of my day.