I had a simiilar experience once with BEHR paint. What brand did you use? Here are a few leads as to what may have caused the problem:
1. old paint especially paint that froze in the winter
2. low grade paint
3. the drywall compound had not fully set
4. wrong type of primer
5. very humid weather
This is not meant to be a definitive list. Just a few random thoughts. Once you determine the issue you will know what to do. Let the paint dry, sand and apply joint compound and smooth imperfections. Then start over correcting what may have been the original problem.