Switch from SR back to XL - totally different effects???

I was on XL for about two months and finally felt motivation and energy but it was giving me a lot of muscle jerks that my doc/therapist were concerned about. Switched to SR for about a month but I kept getting more and more irritated/aggressive and slowly more depressed so I asked to switch back.

I've been back on XL for two weeks and the depression is continuing to increase (anhedonia again, yay....), irritation is mostly gone, I'm getting none of the 'good' effects like the energy and motivation from before and instead crash so hard that I'm taking daily 3hr naps at 6pm. I feel worse off than before any medication bc at least I was AWAKE after work and able to function.

It's like this is an entirely different medication despite getting the exact same one from the same pharmacy.

What the hell is happening?? I wish I had never changed formulas bc now I feel sad AND stupid.