Pregnant maybe ?

Is it true that pregnancies can very in symptoms ? With my first I felt like AF was fixing to show .. But I believe I'm like 14-16dpo . Not exactly sure when I ovulated but I know it's been about two weeks .. ! My last period was a little strange it was just brown spotting for a few days .. Only when I would wipe .. But it lasted longer then a normal period would for me . I normally have a six week cycle but I had what appeared to be fertile cm around the 15th . So I was expecting a shorter cycle  this month .. We'll I've been getting horrible horrible head aches yesterday i had slight cramps and I noticed a brown spot in my cm which I must add is more abundant I normally get watery cm around the time AF is due but I've been getting a mixture of milky cm and thick creamy looking cm . I thought after the spotting AF was fixing to show up but I've seen no sign of her yet , my cervix isn't even low .. And my boobs have recently started feeling slightly sore (which that could be because my LO was with my husband all day and went five hours without nursing )