Check your leg bag - mine had a one way on the top and then a drain valve on the bottom. I don't remember the brand but it was the one i came home from the hospital with.
I found i could go about 2 hours. Sweat pants or loose workout pants were great.
I had a similar setup when I had to use a bag for a week after a particularly difficult cystoscopy a while back. I was able to drive a car and even go back to work with it - as long as I kept an eye on its fill-level and emptied it before it got dangerous.
The bottom line is, I guess, if it bothers us enough, we find a way to live in spite of it.
Good luck, and hope you're finished with it soon.