Lower back feels loose. on the verge of going out on me, constantly. any sugestions? how to make it stop?

Loose back: It is difficult to know what you mean by loose back. If you have not had an injury then you could have a birth defect with a slippage of your lower spine., called spondylolithesis. This is something to discuss with your doctor.

Exam necessary: So many causes for this situation. Examination essential in order to help you. The cause of this "going out" should be identified. Help is available. Suggest exam by a doctor you trust.