Unsure and is this normal??

Hi, my girlfriend just ended our 2years relationship and i feel like crap, i haven't eaten or any drink (water) for less than 3 days and i lost half a stone, im on the sick from work because of all this. part of me wants her back but i think i only feel like this because im not use to being alone again and in a big bed yet or i still love her, we did everything together to fast she moved into mine and we did a room up together and everywhere i look i just see her and it's doing my head in. last night i found out she kissed another lad after a year together this mad me feel loads better and really hated her then and didn't care we broke up, was i eating and drinking again. just woke up and first thing on my mind was where is my girlfriend and now feeling like crap again what do i do? We also had a little girl witch is 7 months old but at the minute i feel like i need a break from her too and was told this is normal so is it? I dont want to tell my ex that i want a break from my little girl as i no she will use this on me when i do want to start seeing her again.

please help help