See your doctor. Your cycle should not be coming this often; your tubal ligation should not have caused this symptom and you need to know why your cycle has changed.
In the meantime, take an iron supplement. You might try taking it with vitamin C, and also take it with a spoonful of olive oil so you won't get constipated.
Unfortunately, tubals can cause these symptoms. It's called Post Tubal Ligation Syndrome (PTLS). The parts of our reproductive system all work together. When one part(s) is (are) removed, it can disrupt the whole system.