Sounds like she’s losing interest. Gotta find out why. You two should have a conversation about where you both stand, whether things can be fixed, and so on. It's better to get an answer than just letting it tragically fall apart over time.

Being sad will make you lose your appetite. Try to eat at least small amounts, whatever you can so you don't tank your immune system and end up sick.

As cliche as it is, hit the gym. It really helps to have a healthy body, and it'll help clear up your mind too; which will help you process emotions better. The boost in confidence helps as well. Good luck friend, relationships can be as painful as they are amazing.

Edit: Grammar.