Hi hun
I had something very similiar (tightening around my bump). I was terrified and thought I was going into labour

. I contacted my midwife and she told me it sounded like a urine/bladder infection and told me to go to my GP. I went to the GP and she examined my urine and it had leukocytes in it - a sign of an infection. I was prescribed antibiotics and after a day or so of taking the antibiotics the tightening decreased and gradually went away. I am just grand now but was so scared. This happened about a week ago.
It was a horrible experiences as I was in agony and could barely walk. I now drinking sooo much more water!!! I hope you are okay now.
Christine