not enjoying this phase!

My lo has just turned 1 and has started being a monkey at bedtime and in the night! He always went down no problems, in his cot, kiss goodnight, leave the room and he would be asleep in 10mins all by himself. Now he screams as soon as I leave the room and jumps up to the cotside. He then bounces and cries out frantically until I go back. Then he reaches up for a cuddle, then he goes back down, but as soon as I leave he does the same thing and this will continue unless I stay there with him. I do this after 2 or 3 times as he gets so upset. Then if he wakes in the night the same thing happens, although last night he kept this going for an hour! Even though I was there, he just kept getting up to be picked up. Nightmare! I tried a night light but its me he wants there and its tiring now as has been going on forr 10 days. I have been told its a phase but gosh I cant wait til its over...