5R55E trans not shifting into OD or 1.

[prerunnerranger]

I ran into a problem driving to a girls house yesterday. I had a rough idle from a misfire and it would stall out. I would have to shift it to park and turn the engine back over yada yada... I was at a red light for a minute and my truck stalled I went through the process and while turning the engine over people were honking at me because there was a green light, I revved the engine to about 2000 rpms and without hesitation I shifted into OD and went to take off but I heard "clank" "clank" coming from the trans and wasn't able to move forward. I shifted into reverse and backed up an inch and shifted back into OD and went forward fine. I got up the street to an incline and the truck just stopped going forward (luckily nobody was behind me this time) I reversed it into a parking lot and parked it for a minute tried OD again and it didn't move, tried 1 same thing, tried 2 and it moved. Now for the question (about time lol) what could possibly be wrong? would I have to replace the whole trans or send it to a trans mechanic, or can I easily fix it? I am in the military so not much free time to go to a shop, and I'm taking leave on 17DEC so please reply fast.