As others have said, you are not wearing the right plug, and it is probably too small.
You need to experiment and try various plugs until you find your favourite. Different styles can be worn for different reasons.
As others have said for doing housework or walking, and all day wear, you will need something with a larger bulb and longer neck so that your sphincter will hold it in place. It might be a little more difficult to insert at first until you get used to it, but remember to use plenty of lube and relax when you insert it.
I regularly wear a jeweled plug to work when I am in the office, and generally have no problems. Sometimes I have to re lube a couple of times but not always.
Just as an added precaution, and more for my own peace of mind more than anything, I usually wear a tight fitting thong with the back pulled up between my bum cheeks and the sides pulled high up on my hips, just for additional security, but it would only give you a short time of extra security, as if a plug wants to come out, it will come out, nothing really will hold it in.