I am trying to catch a Kingdra. Every time I fish in bubbling water at the P2 lab, I don't get it and I have tried for hours. Is my game glitched or am I just unlucky? P.S. I'm playing Pokemon Black
You're just really unlucky.
If you have no luck @ the P2 lab, try Routes 17 and 18 in rippling water as well. Kingdra is only 5% in rippling water, so it does take some luck.
Source & experience (I did stumble upon a Kingdra once).