Hi welcome to Health care magic forum.
Thanks for calling H.C.M.
As the pregnancy
tests are negative, you need not worry about pregnancy, still if you want to exclude the pregnancy, you can have blood for H.C.G.test, or U.S.scaning with full bladder.
After the removal of the I.U.D. due to psychological factors like fear of pregnancy you can have such changes.
Any how you consult a gynacologist for exclude the possibility of pregnancy.
Take a balanced diet, containing green leafy vegetables to cope up the condition in a natural way.