No period and I'm worried

I haven't had a period for almost 5 months now. Every urine and blood test I've taken comes back negative. I am worried something might be really wrong with me and this might effect me having children in the future. My husband and I have sex almost everyday that's unprotected and he 'let's loose' (lol) inside me 9/10 times. So it's not like we are trying to prevent from having a child but something has got to be wrong if I'm not pregnant by now, and I'm worried that's the case. Has anyone else been late and no signs like this? What was the out come? I have a Dr appt with the woman center Jan 20..I hope it's noting serious..):