thank you for your query.
The failure of tubal ligation
is very low ( less than 1 % ), but it is not zero, so technically pregnancy
However, the risks of ectopic pregnancy are very high after tubal ligation.
If the pregnancy is intra uterine, and there are no other medical risk factors, there is no reason why the pregnancy should not be carried till term.
Your emotional moodswings and appetite etc are no reliable indicators of pregnancy.
They are common after tubal ligation, known as post tubal ligation syndrome.
I do not understand why your doctors " think " that you are actually pregnant.
Pregnancy can be easily confirmed by a blood test
and an ultrasound
, so get these done at the earliest.