S.M.
That's actually the typical pattern. Between 3-6 months, babies tend to sleep for longer stretches, and then between 6-12 months, more of them tend to wake up in the middle of the night.
See "A longitudinal study of night waking in the first year."
http://www.ncbi.nlm.nih.gov/pubmed/1934318?dopt=Abstract
It's important to get solid information on what "normal infant sleep" really is, because many new moms are given unrealistic expectations. See
http://www.kellymom.com/parenting/sleep/sleep.html#normal
So the good news is that your baby is normal, don't worry. Bad news is (also) that your baby is normal, so there's not *too* much you can do about it, and you'll probably be getting woken up in the middle of the night for a while. But you can try to go to bed earlier yourself, maybe trying to catch naps during the day (or on weekends if you're employed). Many people have their baby sleep closer to them (crib in their room, co-sleeper, or even crib mattress next to their bed) so that you don't have to wake all the way up and stumble down the hall to soothe the baby. The quicker you can get to them, the quicker both you and baby can get back to sleep. (PLEASE look into the long-term effects of sleep-training or "Ferberizing" before you go down that route. There are better ways.)
I won't even TELL you how long it took my kids to consistently sleep through the night, because I don't want you to jump off a cliff. Figure out a few ways that EVERYONE in the family can get at least semi-adequate sleep that also respects the baby's nighttime needs for security, comfort and hunger. Prepare for it to be a long-term pattern and find ways to cope, and maybe you'll get a pleasant surprise.
Sweet dreams!