When i start my car it goes but after a short time or stop or i shift into reverse or somethin it stops going?

i tried adding some transmission fluid and it sounded like it helped a little bit but still wont go its like its missing gears its a 2000 oldsmobile alero and its an automatic so i am just wondering what could possibly be wrong with my car?? also if it stops moving and just reving up if i turn off the car wait like a min and turn it back on it goes again like nothing is wrong again only for a couple min the only thing else i can say is that lately when i was driving it i would just be holding my foot on the gas and then randomly it would just like feel like it cut out then it would rev up a lil then continue driving i noticed but never got it looked out now i cant even drive a mile without stopping and restarting my car any ideas??