pregnancy after a TL 2 years ago

2 years ago I made a quick decision to have my tubes tied not aware of all the suffering that comes with it.  For the past couple of days I have been feeling moment and pains in my belly.  I have 3 kids now and I am well aware of all the symptoms that come with a pregnancy and I don't lack not one.  I took a pregnancy but it came back negative.  Is it possible to be pregnant and it not show up on a pregnancy test?  Should I request a blood test or even an ultra sound since there is a great chance that it could be a TP?  My doctor is telling me that I can't be pregnant due to the TL.  I recently found out that when I had the TL he tied and cut them so really what are my chances of conceiving a child under these conditions.  

[USF-M.D.-JM]

It is rare but not impossible. The first thing to think about when someone has a tubal ligation and is pregnenat is that they were pregnent before you tied the tubes, Not the case with a 2 year history. But tubes have reattached, very rare but it is possible. And you are thinking correctly in those rare cases the pregnancy is tubal. Home pregnancy test are very good now days, but blood is the best.
Chances highlly unlikely.
Hope this helps
JM