Once again, the uterine volume and the thickness of endometrium closely depend on the day of the menstrual cycle. Assuming you were screened in the proliferative phase (this is when sonographies are commonly performed, as the secretive phase obscures the real picture), your reported parameters are normal for your age.You may have persisting follicular cyst of the RO.

Your tubal banding in 2007 may also play a role. It is yet uncertain, whether it was a silicon band or a clip. In any events, it could cause adhesion, stasis and aseptic inflammation in the salpinx. Your parity information (number of pregnancies, miscarriages, and births in your lifetime) would help understand confounding effects. I assume, you have parity (because your tubes were tied).

For the bleeding, I would not recommend rushing with progesterone therapy in the first place. Anti-inflammatory therapy is more important. Local therapy is the best, if available: electrophoresis with ZnSo4. If this therapy is unavailable, the alternative is to take oral supplement of Zinc, 50 mg per day, for 14 days, starting from the 11th day of your cycle.

As for the progesterone therapy, I trust, you have already discussed this with your provider. The natural alternative is taking sesame seeds (30 gr per day), or sunflower seeds (up to 200 gr per day), from the 14 th day of the cycle to the 25th day. This dosage is adequate to your normal BMI (20.4).