TMI!! Brown discharge!!

I'm 13 weeks and have been expiriencing brown discharge when I wipe mostly just in the first morning urine and when I strain to use the bathroom... I went to the er the day before yesterday and they did blood work,ultrasound of cervix and baby, cervix is closed and they had only found a cyst on my ovary due to pcos. The doctor sent me home and said everything was good and that the baby was fine, but she couldn't give me a reason for the spotting😕  have any of you expirienced this? Where is it coming from? It only comes down one time a day( usually morning) and some days it's less.. Nothing red or pink and no pain and I have refrained from having sex since I got to 5 weeks so this wouldn't be the reason... help please!