Stormageddon

So, my A/C in my 07 Honda Odyssey has been finicky lately. I charged it early in the summer as it was not blowing cold at all, and it was working great. Then it started only working sometimes. Sometimes it will be blowing cold and then start blowing warmer air, and if I turn the air on to the back it stops blowing cold air every time. I changed the relay today and it does not seem to have fixed the problem. Any thoughts?