Is it normal that i can't poop when i need to?

I don't remember when it started but since I was a kid I've hated the feeling of "natural pooping" I guess you could call it. I would hold in poop for literally weeks at a time, often more than a month. This eventually caused me to crap myself at school a few times (some would make it's way out no matter how hard I held it) and I was bullied really badly. I just absolutely cannot let my body push the poop out when it wants to the feeling is so wierd and horrible I've tried hundreds of times to just go normally and every time I have to jump up and hold it in as hard as possible. In time I've learned that once the urge stops I can sometimes push a poop out myself with no problem. It's still really really irritating and I'm now in my mid 20's and still do this. I can control it to a point now where nobody would ever know I had a problem but I just want to be able to stop stressing over something so mundane as taking a shit. I still hold them for days and sometimes a week or more. Any help at all? Even someone who has this problem? I swear it's actually making me depressed.