well your probably preg, but if he is your husband as you say he is then as long as you love eachother nothing else matters.
Go back to the doctor for a thorough examination as soon as you can.
As you have recently just had a UTI infection, this could be still an ongoing infection that has not cleared up compeltely; may be a kidney stone coming down and the cramps in your tummy could be related to that (renal colic).
You may have had your normal period and the other bleeds and shows that you have been getting may be from the urinary tract infection. Kidney infections and kidney stones when they move as well as Cystitis will make you feel nauseous. Stones moving in the urinary tract, will not only give you infections and feelings of nausea, but also tummy cramps called renal colic. When a stone does not move, you will have no symptoms.
The other possibility is that you may be pregnant and are having a bleed and then spotting. So you need to get checked out for preganancy. Sometimes you can experience bleeds when pregnant and this is not a very good sign.
You need a medical investigation to find out the cause of why you are bleeding. As it is outside your normal menstrual cycle, this is not normal and needs investingating. Once a cause is found you can then be given the right treatment.