I have been rethinking this during dinner. You have to start teaching your ds who is in control here. It sounds harsh, but all I really mean is that you can not pander to their every whim, otherwise they learn that they can get whatever they want. Treat it in the same way as you would a tantrum (which will soon appear, believe me. I don't believe in the 'terrible two's', as I started experiencing them at about 15 months! ) You make sure that they are safe and that there is no real reason for their crying i.e. nappy/hot/cold/fever etc. If they are well and otherwise happy, then it is only that they want to feel secure. Checking on them every few minutes usually reassures them.
If you let them get up/feed/co-sleep every time they cry, you will never teach them to be happy alone. I have a friend who is still sleeping in her daughter's bed at 2.5 years. Her dd goes to bed at 11pm every night, the same time that they do! My dh and I have our evenings to ourselves and our ds sleeps through to 7.30am every morning. I was the typical mother who answered my ds's every whim, until my dh made me realise that I was doing more harm than good.
Now, I have a ds who is happy to sit in his travel cot and play or watch CBeebies while I have a shower. OK, we do have the odd bad night (Xmas Eve he woke up at 9.30pm and would not go to sleep until 1am), but in general, we have an excellent sleeper. I am not saying that 'I'm right, you're wrong', just that you are important in this equation too. You need your sleep, and 12 months is not too young to start to let your ds be a child rather than a baby.
However, the final thing is that you must be happy with what you decide to do. If you are happy to carry on getting up in the night, there is no problem. Every parent had their own ideas on what is best for their child, and no-one is totally right or wrong. If we were, we'd be making a fortune publishing our own baby books!