What Does The Purple Bruise Around Penis Shaft Indicate?

I have a purple bruise around the whole shaft of my penis, I have also been feeling the need to urinate very frequently but when I do try it s not a full pee always, usually just a little bit. I went to the doctor yesterday and they are testing my urine for an std but the results won t be in until Monday and it is Friday. I cannot keep worrying about the what if so any answer would be good for me right now..