KittyPaws, you are so not alone, i can assure you. I have had this problem in recent years, I have tried so many things. I am now having to wear 2 pairs of pants, and a panty liner, to the rear, if you see what I mean....especially as I am now wearing skimpy leggings kind of thing. A couple of years ago, I had some of those anal plugs, and tried them, but they were awful, felt uncomfortable, and didn't help really at all.
Then there was that programme, I think on Channel 4, about people with this problem. A lady had very similar troubles to you and I. There first line of advice, was to watch your diet, which, sadly I have to do now, as I know there will be nasty consequences if I don't. Then she was advised to do excercises, similar to pelvic floor ones we do after we have babies.
I have tried this, and along with my strict diet(no baked beans, or processed peas, no fry-ups etc) and I have to say it has helped.
What I do is after going for a poo, I wipe myself as clean as possible, and stand up, then flush the loo. As I wait for the cistern to refill, I do the clench thing, with my bottom, and hold it for 10 seconds, and I do this 3 times.
I have been doing this for a couple of months now, and can honestly say, I have seen some improvement.
I also read that Sorbitol is definitely not to be taken as this aggravates the bowel. This was a bit tricky, because I use Sugarly by Canderel. So I have stopped using this also, and I hope that is helping me also. I have only started doing that this week, but early to tell if it will make a difference, but worth trying.
You can also self-refer to a bowel clinic, run by the NHS, go online to find it. You do not have to go through your G.P., and they will investigate your symptoms and make suggestions, and finally try to sort out where your problem stems from.
This would be my next port of call, if I am not successful trying to sort it myself.
I hate it though, so nervous to go out, I carry wipes and liners with me all the time, try to go to the loo before I go out, but sometimes it just happens without warning, and all you want to do is go back home.
I really feel for you, but as I said I think it is quite common, but the solutions probably differ for each person.
Good Luck, and let us know how you get on, going forward.