I also feel familiar with this kind of feeling, despite not enjoying/suffering from a similar situation for some time now. Personally I utilize two different techniques:

To-do lists:

I usually would list all the things I want to achieve the next day. The order is quite flexible, but I have a habit of starting with the most boring thing if I'm feeling positively driven, and conversely with the easiest or most pleasant task if I'm feeling down.

Exercise:

Sometimes the positive emotion has been so overwhelming, that I have been unable to focus on anything remotely intellectual or abstract. So, to me the answer is to go to the physical level: go for a run, bash my drumkit or anything that is both physical and enjoyable. I've found it very useful to ride out the sort of excess enthusiasm and then pick up writing or reading again.