Subi has no power

[subiman7]

Hello so we have a 2006 Subaru outback 2.5i xt limited. Has 186k miles car was great but the other day I filled it up and drove fine for a little while but the started loosing power it was like all the car had to keep up speed. Once slowed down it wouldnt get back up to speed without running at high rpms to get up to speed. I limped it home the best I could which wasn't easy and it doesn't even have power in reverse to get up a little slope next to my driveway. I don't even know where to start this does have a turbo and I did put regular unleaded but I'm not sure the gas would make that much of a difference to make it not move or make turbo work properly could low antifreeze cause turbo to not work right? I need help and will do any advice given. I have very mechanically inclined but I've never had to mess with something like this. Thank you and be blessed.