Play some limit. Definitely play some multis, even if they are cheap ones (I'll reiterate how soft the UB nightly $10 tourney is). I like the play the first hour or 2 of the multis while playing a ring game to keep from getting bored during the early stages of the multi (since for me, boredom usually means overplaying crappy hands).

I have played some stud8 for a change up every so often. It's pretty much a card-catching-fest at .5/1 and 1/2, but it's something different, while still very similar to o8. I do not recommend multi tabling stud8, however.

Session by session results are not ideal, for the reasons you mentioned.

I've had a roughly break-even December, and haven't been able to make anything significant in January up till today. Limit O8 is the main culprit, but even in small PLO games it seems that I have become way too dependend on the cards. On the one hand I have a huge problem winning a showdown, and on the other hand I have trouble outplaying my opponents, who simply call me down everytime since they expect me to lose a showdown.

What you should do depends in the first place on your skills and your character. If you are still playing well, then I suggest trying to play through it. If it affects you then seek a change of pace, by playing SNGs and MTTs. There you buy in once and after that you can play without any concern for money.
Also, a change of site can be healthy; you will have new opponents with different playing styles, so that even playing one table can be a refreshing experience, especially when you get a huge first time bonus...

Keep us informed about your experience, Goop. I've never been able to work that, successfully. The differences between ring and SNGs are too great for my feeble mind to accomodate at the same time.