So I was turning the BB and I noticed everytime it got stuck, I forced it and it "jumps". This repeats every full turn I make but the BB does not go deeper. Have I stripped the BB? Is it useless now?

Need more info.

Are you talking about spinning the bb SPINDLE and it is getting stuck, or are you talking about the threads on the cupos holding it into the frame.

THe only advice I will give is that you should never force the cups to turn... if you can not thread it all the way in by hand (no tools) then something is wrong.

stripped threads?

a shop with a thread chasing tool should be able to fix your BB shell threads.
As for the BB itself, it's hard to know if it's stripped or not until you take a closer look at it.

You'll probably want a shop with a top to clean things up in there. Odds are you've stripped it. However, I've seen a couple cases with soft aluminum or plastic bottom bracket cups and steel frames where the frame turned out just fine.

The spindle might be stripped. The BB shell can be stripped too? Let's say it is the spindle: what happens with that?

If all else fails and the frame is worth saving, you can try the Velo-Orange threadless BB (clicky image):

The BB's usually have steel shells so unless it's an external cup setup where they use aluminium bearing cups it's far more likely that the frame theads have been damaged. And given how loose some BB's are when threading into the frames this is entirely possible.

The sad part is that you can't put metal back on easily so the suggestions to have the threads chased isn't going to help. Chasing only helps restore damaged threads that were cross threaded. It won't do anything for threads where the crests have all been shaved off by a badly fitting BB body.

I think the VO YST threadless BB is a higher quality item, but I've seen plain silver YST threadless BBs with 20 spline ISIS/octalink being sold for about 1/4th the cost.

either way, it's best if the BB is faced, which requires chasing the threads, if installing a YST threadless BB.