Masturbating And Pregnant

I just had my first appointment and everything looked great. Today I decided to give myself some pleasure because my boyfriend was working all day and I work nights. When I showered I thought I seen something as far as blood or brown coloring in my discharge. I went to the bathroom on my break and there was some brown coloring in my discharge. I didn't get worked up because I didn't want to scare myself or stress my baby. Should this be something I should worry about and have another ultrasound done. I think I'll be okay, I'm just scared of having another miscarriage. Any advice?