What Is The Bruising Feeling On My Lower Spine?

Hello, I am 38 yr old woman, 5 3 144 lbs. I have been recently in the past year been diagnosed with Ostiopenia, Diabetes, and had my tubes tied. Yesterday when I sat down on the couch I about flew off because of an unexpected bruised feeling in my lower spine area. I asked my husband if he could see anything. I don t remember hitting it and the first thing I thought of was maybe I got stung or bit by something and didn t know it. He didn t see anything. I have had a sore throat for two weeks now, which I have gone to the Dr. for and was told there was really nothing antibiotics could do. But gave me a Rx for BACTRIM DS to fill if I don t feel better. I have also felt overly exhausted lately which I didn t really think anything of because I have a lot going on. It is this bruising feeling on my spine now that has me concerned because I have no explanation for it. Just wanting to know if this is something serious that I need to go back to the Dr. for or not to worry, I have to little ones at home that I have been trying to keep my distance from because I don t want to give them this sore throat but this now worries me more.