My relationship

I need some advice please I've been with my partner just over 4 years we've had our ups and downs but lately he's been acting strange, if I go up the shop and say I'll be 15/20 mins if I'm back a little later say I've been gossiping he will go mad, if I'm not back from work within 5/10 mins he goes mad and we have a massive arguement, he even timed me earlier going to the said I left at 15.31 it's just strange I don't know what to do, he seems to be acting real possessive and stuff and I just don't know if I'm over reacting or not... any advice would be great please.