2 yr old not sleeping

My 2 and 3month old son has never had a problem sleeping. 12 hrs overnight and 1-2 hrs in the day. He has never gotten out of his bed,and usually doesnt take long to settle,he might sit in his bed for a while befor he goes to sleep but is never distressed. and usually just waits till I go in and get him after he wakes.  Recently he woke up during the night and came up to our room, and just put him strait back to bed. During that week it got much worse going from getting up to 2,3,4 times a night, I put him in our bed early in the morning, only as a last resort, as my partner and I both work, but over the past 2 weeks he has been getting up more during the night and just wants me to cuddle him, and also it is taking me like 2 hours to actually get him to sleep at night. (bedtime is usually 7-7.30). I have been putting him back to his bed repeatedly but he keeps getting out or just lies there with me, in his bed awake. If he falls asleep and I leave he wakes up hysterical and we are back to square 1. Last night I actually put his couch in our room and let him go to sleep there, but this was at 4.30am after being up from 1.30. Im not sure if this is just a phase and I should just keep putting him back to his bed, as time consuming as it is, but he wont even let me leave anymore. I also tried using the gate in his room but he just got absolutely histerical. I have also tried esplaining to him he will get a reward if he stays in his bed, he only got up once that night but the next day was back to the same behavior. Does his day sleep need to be cut out, I really dont think so because he crashes at 12.30, 1ish when he goes down. Does anyone have any advice. Please. I am so tired!!!

[margypops]

How long does he sleep during the day perhaps cut the time of that back,Has anything happened to upset him  , you are putting him back when he gets out of bed so that should work ,who has him in the day time could there be a problem there ,is he in Daycare, check out anyway he could be upset.