Hang in there. My second was a terrible sleeper, and the Rock-n-Play helped for a while, but she grew out of it pretty soon. I think at 5-6 months we turned a corner; she still was a bad sleeper, but she gave me much longer naps and intervals to sleep at night.
I didn't do anything different with her than I did with my first, who was a fantastic sleeper, so at least I knew it was not my "fault." So never, ever think that you are doing something wrong. Some babies are wakeful and there is nothing to be done.
Like everyone is saying, let your H do some of the work. Even though H worked and I stayed at home, I let him take weekend nights. That way, I always had that time to look forward to when I was in the middle of a particularly rough night.