Why Do I Get Pregnancy Like Symptoms For A Month And Then Have My Periods?

Hi, we have been trying for a baby for almost 12 months now - and each month I am noticing changes or signs in my body that could be pregnancy - but I end up getting my period. I turned 30 last April, I have a 26 day cycle (on time every month) and this month we feel we gave it a really good go at timing to fall pregnant.
I am due for my period in 2 days and yesterday and today have noticed 1 - 2 spots in my pants each day, of 1 red spot and 3 brown spots. I have not ever experienced this before - and think that I may be pregnant this month. I have been very emotional the last 2 weeks, very sensitive and teary to really silly things. I have been aching and very tired every day and just yesterday my breasts became very sore, and I'm still experience an aching feeling in my uterus area like a heavy period (this has been the case for the last 10 days). Hoping you could shed some light on this for me? I will look at taking a pregnancy test in a few days I guess?