Not taking these meds consistently is going to mess with your mood. You really do need to give up the drinking while on these meds because you are either going to end up skipping doses which will cause issues, or you are going to discover that alcohol and these particular meds are not very good friends. I take lithium myself and have taken abilify in the past, so I do speak from some experience.

If you are committed to allowing these meds to really work, you have to be consistent with them and not mix them with alcohol except perhaps as a very small amount on the very rarest of occasions. This is part of your responsibility and dedication to doing all you can to maintain some stability. Sorry to sound so firm about this, but messing with your meds is just not going to help yourself at all.