How do other mothers go through this night feed problems?

My baby currently (3month) sleeps 7 hours then wakes up for a feed and sleeps another four to five hours after the feed. However he only feed on one breast at that feed and I have to pump the other breast which completely wakes me up after all these are done. And I usually couldn't go back to sleep for another hour or sometimes two hours. Does anyone else have similar problems?
I can't kip the pumping because 1. my breasts are uncomfortably full after 7 hours and I know I can't feed him for another 4 hours. 2. it might decrease my milk supply during the day if I don't pump at night (is the true). I also tried feed him a little bit on both breasts but then he wakes up a lot earlier than 4 hours. I think its because the fore milk is too watery to last him too long. Any suggestions are welcome! Thanks!