No period, yet negative???

Yeymi • Navy Wife⚓️ Mommy of a precious baby girl 👶🏼

So my husband and I have been ttc for 4-5 months now. In October I didn’t get my period at all. The first week of November my period shows up but it was different. It wasn’t as heavy, only lasted 2 days and a half, didn’t get any warnings, and didn’t even feel cramps, which usually I always get. Here comes December and according to my calendar I was suppose to get it the second week of Dec. and it’s already the 26. I took a pregnancy test on the 16th and it was negative. So I’m wondering is it normal that period is skipping a month. I have never skipped a month and I’m would ask my gynecologist but I don’t have an appointment till the end of January.. has this happened to anyone? I mean I’m really trying to get pregnant here!