Well, you could just be going through a hormonal change which happens. Not like THE big change of menopause but a shift of some sort. You'll get symptoms like this. Since you've had a tubal ligation, you have to be careful about pregnancy. It doesn't happen often but depending on how you have it, pregnancy can occur after even though it was meant to be permanent sterilization. If the clamps came undone if that is the way you had it done, you can get pregnant or if you had the tubes severed, scar tissue can form in such a way that it makes mini tubes that have severed back together. However, in both of those scenarios, any pregnancy that takes place after a tubal ligation has a high rate of being a tubal/ ectopic pregnancy. Those are not viable and actually can be fatal to the mother. So, take a pregnancy test. And if you continue to have strange symptoms or period issues, go to a doctor for a blood test to rule out pregnancy for sure. good luck and let us know!
I think you should go to the doctor. Although i have heard your tubes can untie.