Isphagulla husk ( Psyllium) will help. Take at bed time before going to sleep with milk preferably two teaspoons.
You should see a doctor for a change in bowel movements, it could be really serious. That said, I take magnesium citrate every night. You can purchase pills. They're easy to find. Your body needs magnesium anyway for a lot of things, one of which is helping your intestines move your bowels. It also is relaxing and helps with sleep. The kind of magnesium you get is important, because some don't have as much laxative effect. There are several kinds, I think magnesium citrate works best. There are no unwanted side effects, and it doesn't cause cramping like other laxatives.
wow, that's a lot of days. You must be uncomfortable. Get an enema at the drug store. Not super fun, but you have to get this moving. Let me know if that works to start the process for you. And if you become ill, then see your doctor. Feces can impact the bowel when it sits there just like a bowel obstruction. So, you really want to get this moving.
We are definitely more prone to constipation as we get older. Fluids is a great way to keep us regular. Up your water consumption. Don't overdue fiber. A cup of grape juice a day helps, a handful of prunes is like a laxative.
Your pelvic floor could be weakening. The do a test for that which is not particularly pleasant but when that is your issue, a physical therapist that specializes in this can fix it. So, if it continues and these simple remedies I suggested don't help, then see your doctor.
Oh and any new meds you are taking?