I am also pregnant and after doing hours of research, because I too have had cramps on and off very mild and only lasts a few seconds, has found that it means your baby is implanting more into the uterus. If it becomes severe or is also followed by bleeding then see your doctor because you could Miscarry. hope everything goes well for you
The cramping could be from the UTI and from your uterus stretching as well. I had light/mild cramping off and on throughout my entire pregnancy so far (I am now 26 weeks). I can understand though why you are so worried. If the cramps get too bad or you start to spot call your MD. Good luck and I hope they are just growing pains.
Cramping is really common in early pregnancy. In some cases it can mean miscarriage, but often it's because your muscles are explanding and getting used to the growing weight. You could have these cramps last for weeks or just a few
days. As long as it isn't severe pain it should be ok.