New problem with my new 98 GSX :(

[CoreyGSX]

I just bought a 98 GSX and i was cruising around town and i hit a rough spot of road while doing a second gear pull and now when i go to take off either in first/reverse it feels like the rear tires are catching and releasing and bouncing up and down. Just wondering if anybody has had this problem before or any idea of what it could be. I've tried calling my local speed shops but no one is answering their phones. Any help is appreciated.