I still get tired very easily, but I now have a little bit more energy now than I did throughout the first trimester. (I was on progesterone until 13 weeks, so that made things worse for a bit.) Unfortunately, it was only very recently (~17.5 weeks) that I started to feel human again, and not constantly sick!
(although, if I don't rest up now and overdo it, I start to feel bad again. The sickness has been replaced by bad stretching pains / backaches, but that's better than nausea/dizziness!)
My ob said it's 16 weeks for most women, if that helps...