Help!

 My husband and I started TTC last month once we PCSed to Alaska. My last period was August 10-14, and my cycles are usually only 22-25 days long.. I am on cycle day 48. I've taken hpt, and a urine test at the hospital on post that came out negative. I am bloated, I've been throwing up so much and my back is killing. Is it possible that these are false negatives and my hcg levels are just low? Or what else could be wrong? I've never just skipped a period in my life.