Struggling with Bathroom Anxiety at 34 Years-Old

Okay.. so this may be an odd inquiry of sorts, but I seem to have difficulty using the bathroom for number two, if anyone is around. It's been this way for as long as I can remember, too. Even as a young kid, I would wait for my mom and dad to leave home, and immediately I would be overwhelmed with the feeling of having to use the bathroom. But when they were home, I didn't have that feeling at all.. but I most certainly had to go. It's a bit hard to explain, especially since I don't quite understand it myself. But I'm not 34 years-old, and struggling just the same. I mean, even around people I'm very comfortable with, like my boyfriend and our kids - it doesn't seem to matter, I still have a rough time. A big part of it I've come to realize, is the constant interruptions. Like, as soon as you enter the bathroom at my house, someone is at the door, exclaiming that they need it (and depending upon who it is, they will literally wait right outside the door, until you come out.. ). It's really frustrating, because I will know that I undoubtedly need to go, but regardless of the discomfort and everything - I sit down, and can't seem to do it. I literally HATE it. Any advice would be greatly appreciated.