Need help! Rear end feels like it it will slide out
 

I have an 00' seville. Heres the problem. I just bouggt this car 3 weeks ago seemed like everything was fine when i got it just needed brakes replaced. Then i went on my first distance road trip thats when the fun began. EVERYTIME i go over any bump it feels like the rear passenger end wants to jump off the road. My steering wheel is straight. It scares the hell out of me. I just recently found out the wheel bearing is bad on the passenger rear could that be the problem. Ive not noticed any sounds no uneven wear on tires. It just scares me because i have three children. Please if you have any idea let me know. Thanks!