Verified answer

sounds like your having pressure problems could be just low on tranny fluid have you checked it depending on the mileage it could need a filter change.. as far as the abs and brake light deal that shouldn't have an affect on the transmission .. the car hasnt been wrecked has it.... the abs and brake usually come on at the same time due to a faulty or broken wheel speed sensor..

i just red back through it i see your slip light is on its probably a speed sensor making your car think its spinning not sure about your car specifically but in general... when gm cars sense wheel slip it will cause the tranny to slip and cut horse power to help you gain traction could just be simply disconnected look at all the wiring behind your brake rotors

if it's a jerks when shifting then its a bad Torque Conveter.