I'm sorry to hear you're in the dumps, I know what that's like. I also know what the whole ex thing is like as I sometimes see her at the gym and it sucks goat balls. I try to go when I don't think she'll be there.
Just try to control the controllables. Don't go to websites to "peek" or do anything else that may put you in a bad mood or make you unhappy. In other words, don't ask the questions (with actions) that you don't want to know the answers to (or that you may want to know but won't do you well in knowing).
I hope you feel better soon.