IUD out.period not insight.unprotected sex.pregnant?

After 4 years I got my Mirena IUD out because my husband and I decided we would like to start a family. Got my iud out feb 11th, had unprotected sex on feb 14th. The 15th&16th I had some of that light spotting that you may get before your period that is rusty colored, and I had one probably pencil eraser size sticky clot on the 16th, some lower abdominal cramps felt like I was going to be getting my period. And since then nothing. We have had sex without protection since then and i have not had any spotting or cramping since. I have noticed I have gained about 3 pounds in the last week or so and I have this little pooch in my lower abdomen and looks like I’m pregnant, bloating. Took a pregnancy test yesterday morning...negative. My doc says my period could take 4-6 weeks to come. I’m trying not to stress but can I be pregnant even if I haven’t had a period since taken my iud out? I haven’t had a period in 4 1/2 years. I never knew so many things had to be in align for a woman to get pregnant, and since joining Glow I have learned that is not the case. Any one out there been in a similar situation or a medical provider that could guide me on what I should do?