Just sounds like you need to get back into some hardcore practicing again. Or maybe those you're playing have improved. Honestly, if you're starting to take more losses now, it's a sign that you need to start re-analyzing yourself more and spot your mistakes. You've gotta keep yourself sharp at all times against everything, however you can. It's what my old mentor taught me, and it's why I only main one character.
Free Step Dodge
iHajinShinobi
Zeo
Characters aren't the problem as I only use Akira and Hayate. But I'll beat the majority of people. But when I get to people like XCalibur, E-Mann, Steady, more respectable players I just can't follow through. I had a habit of losing the majority of the time to the latter 2, but I would occasionally win and always put up a decent fight.
Zeo
I guess what I need is a nice long session with someone who can beat the tar out of me. Maybe that'll force me to step it up. Labbing doesn't really seem to help me as I still remember virtually every BnB and combo + setup I was using 4 months ago.