I got my oil changed Saturday at the same place I always go to. Drove a short distance Sunday, didn't notice any issues. Today (Monday) I go to get on the highway to come to work and my check engine light comes on and suddenly I can't accelerate without the RPMs going up like I'm revving the engine. to go 50 mph, the tach was at 5. I plan to take it back to the place that changed the oil this afternoon but I'm really scared to drive it...what could cause this?