You sure you put the right springs in the right locations? Make sure you didn't put the front springs in the rear. I'd suggest getting some friends who have worked on cars before to help you next time. I'm all for trying to do it yourself and trying to learn how, but you really need to read up on how this stuff works, how to properly work on a car, and watch people do it first. Consider what would happen if you might be going around a turn and the bolt you forgot to torque down came out? We're not talking about just money here when you screw something up, we're talking about your safety and personal well being...
Good luck bud