It does not take much impact to damage the frame or unibody in cars today. The cars is designed to take most of the impact, while protecting the passengers. Therefore, if your car is slighly out of alignment, it can cause a lot of problems. The best thing to do is have a body shop measure your frame to determine if it is damaged or not. You may not be able to see this damage by eye. This is something I would not guess at. Have it checked to save you many headaches down the road.