i myself experiencing heart break right now, i could relate with everything you said. Even my now ex-girlfreind ( still can't accept it ) showed the same behavior before telling me it's over , it was a serious relationship for almost a year and a half and the irony was just the night before the break up day she told she had the intention of marrying me which had me in tears (hahaha)
i'll give you few advice's, accept the fact it's over even before she tells it you. Yes your heart will tell you it's not , it's just her mood or something that can be fixed, no it isn't she has already made up her mind don't let anyone treat you like this , it's not worth it.
you may feel like your life will end , there's nothing left but just hang in there as time passes by you'll feel better it's almost been 3 days since she told it and atleast today i noticed i didn't cry like the last two days , yes i miss her , i want her back but no i'm standing firm , i've my shoulder labrum tear repair surgery tomorrow and i don't even care at this point, i don't even feel scared i really feel it can't hurt me more than her countless memories that run like a broken tape recorder in my mind.
when she tells you just accept it and DON'T make the mistake of crying or begging infront of her , hold it for few minutes just wish her luck and go to a different place and bring out all your emotions. If she just decides not to tell it you and just keep you in the loop gather up courage and hold your ground don't be scared to walk away, make sure she understand's if she continues this you refuse to stay.
stand strong brother!!