iud taken out now trying to have a baby..

me and my boyfriend have been trying to have a baby... i got my iud taken out a little over a month ago... i have been really tired and have been having cravings a lot.... my boobs hurt like hell all the time.... and i cant sleep at night cause i cant sleep on my stomach cause it feels really weird but everytime i take a pregnancy test it comes up negivitive... what else could be going on??