I gave birth 3/29/10 and I am nursing. I recently started her on a miniscule amout of solids for about a month. I am taking synthroid I was constantly monitored for my thyroid. My dr, has lowered it and increased the dosage since I gave birth. He recently increased itfrpm 0.1 to 0.122mg. I am also taking pms-sertraline since 08/18/10, started with 50 mg, increased to 100mg since. I have been spotting, and getting periods since may 26/10 till sep 25/ 10. I didn't get my period yet, today is Nov 05/10, I took 3 pregnancy tests since than, and all came out negative. I also took a blood test, oct 27/10 also came out negative. for the past 3 days I feel cramping like I'm getting my period , but nothing is happening. I'm 28 yrls old. what should I do? do I need an ultrasound? I'm anxious.