Well, every pregnancy is different. Many women feel pretty good if not great during the second trimester. Talk to your doctor about your fatigue and leg pain for guidance. Sorry you have that!
I'm 9 weeks and am exhausted all the time and short of breath. I can't sleep at night and when I try to take a nap during the day my 3 kids won't let me so and at night time either 2 of my youngest wake up screaming about something or my 8 year old is walking through the house going back in forth from the bathroom to the kitchen to his bedroom & on top of all of that as soon as I get comfy and am about to dose off I have to pee I'm like OMG are you serious and then it takes me 3 hours to fall asleep by of the pain in my back and in my legs and ribs it's crazy but I still completely understand what your going through it kinda feels as if you haven't slept at all...
Also I can barely do anything in the house without wanting to lay down like our dish washer went out the other day and I went out for a few days and came back the sink was full of dishes well I went to wash them and it literally took my 4nhours to wash them by I kept taking breaks be I was so tired I don't ever want go do anything now I feel so exhausted and the headaches I keep getting are crazy.