R.K.
We had a similar problem with my son back in January. He was sick and was waking up, so we started giving him a bottle (he hadn't been eating very much, and we wanted to get something in his stomach). Even after he got better, he kept waking up - it had bacome almost a routine. I was pregnant with #2 and due in a few weeks, and decided that there was no way I could have my older son up in the middle of the night while I was also trying to deal with a new baby. The next night he cried, I went him to him but didn't pick him up (rubbed his back) and that was it. He cried for what seemed like forever - and my husband got angry with me - but it worked. He stopped waking up in the middle of the night. Since then, he has gotten his molars and has had a few nights of waking up, but if it starts to seem like he's forming a new pattern, I quickly nip it in the bud. I would rahter have one night of fussing and/or crying (and little sleep) than many, many nights of uninterrupted sleep!
Good luck!