What to do during an anorexia relapse?!

You're obviously trying really hard, here, have a smiley face :).
I am also going through this.
When I feel afraid, I think of things like this. Nothing is set in stone. Any weight put on can be lost, any weight lost can be put on. Don't worry about getting carried away, or getting hooked on extra food. Worrying about it constantly is really just wasting life. There is plenty of time.
Don't concentrate on gaining. Think about being happy and healthy.
Don't record what you eat. Don't think about it. Just eat healthy food regularly, eat fruit and nuts in between meals. Eat regular amounts of things that are good for you and snack in between.
Go out for ice cream/ other things with friends. Ice cream is good and combining it with something social makes eating it less daunting. Mindlessly eating nutella out of a jar with a spoon also helps :P. Eventually, you'll slowly and healthily gain weight.