Can anyone say what this could be

I been getting a lot of this discharge late its like brownish mucus discharge. Im 12 weeks pregnant i went to er to get checked cause i also get random pains on my right side of stomach somedays and it last all day.but when i went the discharge was gone and todaay its back and its just starting to worry me. I see my doctor on Tuesday but was just wondering if anyone had any in sight on what it may be. I had a molar pregnancy back in September and got pregnant again in October something i wasnt supposed to do and was a completely accident. But i have seen the baby and baby has heart beat and healthy but i stilll feel so scared and this is still starting to worry me.