HELP!!?!!

Hi guys, Im becoming pretty desperate for advise or even your stories to tell me what im going thru is very normal or not lol

I have a 2 1/2 yo who is ossessively saying 'mine' but not like any other story ive heard from other parents.. this is ridculosly constant throughout the day and worse (beign a bad sleeper anyways) he wakes serveral times durning the night SCREAMING - "Mine...this Mine...that" and gets very upset and is convinced someones taken something of his.

He has been at childcare since he turned 1 and he only has 3 weeks left before i pull him out to go on maternity leave. Im hoping so bad he will settle once hes out of childcare, but i would LOVE to hear what other parents have done to help there sanity in this situation.. im literally pulling my hair out and as much as i try to be understanding cos i know it must be very hard at childcare for him, i find myself having to just walk away from him at times or i know ill go crazy!

Couple occasions for example, hes has this massive screaming tantrums cos he wants one of EVERYTHING and ill cuddle him and hell be holding onto 5 or 6 different objects and dropping them and crying and the whole lot... sooooo frustrating!! He has had a bad cold when doing those tanties but still i dont think now hes better there going to stop!
Im gonna go nutty if he gets worse when my next bubs comes and he hasnt grown out of this!!!!