Yikes! I understand ur going to do wut u want to do and thats fine everyone needs to experience every aspect of life,even heartbreaks, but know that ur walking a fine, fine line. U said u just broke up, think about it logically, dont u think it's too early to "just be cool", arent u concerned with UR feelings? Do u think he will walk on egg shells to prevent u from hurting any further? For example, wut if u go to this get-together & theres a girl there who's eye-ing him? Are u going to be ok with that??? Are u ok with him not treating u like a girlfriend anymore? These are things u should think about before making any brash decisions. U need time to heal & for urself! U just spent 4 years of ur life with this guy, thats 4 years neglecting urself as an individual. I personally would avoid hangin' out casualy at least for now, there are way too many emotions to try and pretend everythings ok. Hope this helps :)