Cramp/pressure

So last week I had a very small amount of rust colored discharge. Went to the doc, said it was mostly old blood and did a urine sample to see if I had a UTI. She also checked babys heartrate which was perfrct, 157. Two days later, i had a bit of green/yellow discharge. Doc called in antibiotics for a bacterial infection. At this point I've had lots of cramping and pressure in the very front part of my stomach. I am on day 3 of the med and yesterday was great. No issues. Today, cramps and pressure are back. I'm beginning to think these are contractions/Braxton hicks. We have an ultrasound scheduled for Tuesday to check gender. I'm currently out of state and 16 weeks pregnant. Just wondering if anyone else has experienced something similar?