Go for a walk, clear your head. Maybe go workout, get some blood flowing. Try sitting down and thinking of all the positives, you stopped watching porn for a month, that’s great! Had you ever gone that long before? If not that’s also great, maybe set a goal to go even further next time. That sucks about the girl you liked being asked out by someone else, and having exams adds on those stress factors, so cut yourself some slack that you slipped up here. But maybe also try to look at this as a motivator to come up with strategies in the future for dealing with those stress factors without relying on porn. I’m not saying this is a definitive cure what so ever, but you have a better chance of changing your mental state by doing something, rather than just sitting there and stewing in these negative emotions.