I'm also a girl from Germany with that same problem.
I also can't poo when other people like friends or colleagues are around. I always the feeling that they can smell it and judge me..I know that this is stupid and that everybody does it, but I still can't change my behaviour!
The worst time for me is being at work. I just can't concentrate when I get the feeling I need to go to the toilet and feel bloated.
I try to take a deep breath and thinking that this is just a mental problem, but it doesn't help anymore. I also tried to pinch myself to be distracted - doesn't help either.
It is getting really bad as I start to stay away from work...do you (or anyone reading this) have a hint how to cope better with it? I know (or guess) there won't be a 100% cure for this problem, but I really need help!!