Hm, your symptoms are strange, aren't they? Sometimes, gulp, tubes being tied can fail. If you had the clip method, the clips can come undone. If you have the surgical cut method of tubal ligation, scar tissue can form in such a way that the tubes sort of fuse back together and make a path. Unfortunately, with that, a possible pregnancy post tubal ligation is often ectopic. I would take a test. Have you done that yet?
You were pregnant before, does it feel like this?
I'd take a test. Then go from there. Have you gotten regular periods after ligation? What is happening with your cycle?