2008 CEL code p1121+drag

First off, I've read through several of the most recent posts on this code, so I know it's mostly harmless and I've already had it come on for a couple of days before going right back off. I've had my '08 Prius for about 2 years now. My mom gave me hers when my Ford was deteriorating faster than I could get it fixed. This is the first problem I've had with it in that time. The first time the code popped up was the day after I accidentally overfilled the gas tank. The auto shut-off at the pump kept cutting off every half gallon once it got around 3/4 full. CEL came on with code p1121 and before I could make an appointment to get it checked, it went off. No codes or lights for a month. About 2 weeks ago, someone backed into me as I was driving through the parking lot at work. The insurance company told me to take it to either Service King or a Chevy dealership, so I chose the dealership as I've had issues with SK in the past. Just before dropping it off, I filled the tank as it was nearly empty and I didn't want them giving it back with an empty tank. The pump was apparently broken and the auto shut-off didn't work. It just kept pumping until I noticed gas pouring down the side of the car. I shut it off and ran inside to tell the station attendants and then went on my way to drop off my car for repair.

Yesterday, I picked it up. I could immediately tell something was wrong when I started it. The gas engine usually kicks on after a couple seconds to warm everything up, but it took about a minute. I started to drive off and it was like I was dragging or pushing something. I've had engines bog down before, but that was usually a throttle issue (thank you, Ford) or burnt out heads and a busted timing chain (again, Ford). The light came on as soon as I got home, so I pulled the code and I got p1121 again. I didn't see any others. Could the 2 issues be related or is this 2 issues at once and I'm only getting one code?