advice?

Well my periods were usually spot on between 28-32 days. In September of last year, I quit my job to travel with my husbands job, in hopes that me not working would help us conceive. Well it didn't. I had a period in September but once October came around I didn't. And it's now January and still haven't had one. All pregnancy tests are negative. Being out of work, I have gained weight. Could that be a reason? Anyone have any advice? I'm trying to wait to see a doctor bc they tend to get expensive.