Cannot drive over forty mph, shuts off when at a stop

My problem started when I drove my truck first time ever in the (minus gear) (low gear) because I tried to see if that was my four-wheel drive. Clearly it's not! I did that on one of the horrible winter storm days we had. Ever since then my truck has not been the same, it has not been working correctly. I messed it up. I tried switching the gear up to the (+) sign (high gear) then back down to the (-) sign gear after I felt something funny I think, if I remember correctly. The gear shift was no longer sticking in neither of those two. So I shifted the gear in Drive and drove it home. The whole time there was a clicking sound. Still to this day there is a clicking sound that won't go away. Only that day it did not allow me to drive over 40 miles per hour. And my truck kept shutting off every time I stopped at a stop sign, at a stoplight, every time I came to a complete stop period; When my truck is still driven, it still shuts off every time it comes to a stop. Also ever since that day my oil light comes on from time to time but blinks off and on real fast. No I don't need oil. I have not checked to see if I need transmission fluid yet.