darface, all of us, babies too, go through sleep cycles which mean that we do "semi-wake" every 45-60 mins right through the night. For us, we know how to settle ourselves back to sleep again, and we are usually not really conscious of having "come to" unless something happens to really wake us up at that point.
However, what I suspect is happening with your DS is that when he has one of these wakenings, he doesn't yet know how to put himself back to sleep - so he wakes up properly and cries for you. If you want him to sleep through the night, then you have to find a way to help him get back to sleep again by himself without needing you.
One way of doing this, but it is exhausting if you have to do it single-handed, is to do the following:
when he wakes up, go in to him and gently lay him back down again, soothing him but not talkingi to him or making eye contact. Each time he cries or tries to sit back up again, lie him down again. It can take many many repetitions at first though, but eventually, I promise you, he will go back to sleep. When he wakes up again, you repeat the process. Trouble is, it is absolutely exhausting to do it on your own. I suggest you wait until your DH has a bit of time off and then do it together.
I would also suggest that you read the Richard Ferber book about babies and sleep. Even if you don't want to adopt the approach of "controlled crying" (which is what he advocates, and it does work, but it does involve listening to a lot of crying) it is full of valuable information on babies' and children's sleep patterns.
Good lcuk! It will get better (I speak as mum of 3 boys none of whom just slept through on their onw).