I Finished My Period Nearly A Week Ago But I

I finished my period nearly a week ago but I have had some bleeding. When I wipe I find a light red discharge and I have had some in my underwear. I have had a headache and feel really tired. I'm not pregnant. I was ill a week ago with bad abdominal pains and feeling generally ill. I went to a walk in clinic and the doctor took a urine sample and said that I was positive on 3 out of 4 areas for a urine infection. It's doesnt sting when I wee and the abdominal pains have gone now. I'm really worried what could this be??? I drink about 2 litres of water a day but my wee seems to be quite concentrated still. Please help! What should I do??