It has been 2 weeks and 3 days since I last had intercourse, I was due on my period today (16th february) but I haven't come on, however sometimes my periods are irregular.
My breast are painful to touch, seem bigger and also I have noticed veins in my areolas?/around the nipple, and also going through my breasts, which I have never noticed before.
When would be best to take a pregnancy test?

2 weeks from today, and if negative and still no period, every few days after that.

Okay, thank you :)

And to add. Be sure it is first thing in the morning as soon as you wake up. ** For best results

You would not be having pregnancy symptoms this early, in any event.

At first I thought I was pregnant which is what my last question was about.
But I then got my period on the 17th feb so I thought I couldn't be pregnant, but then my period only lasted 2 days, and now (19th feb) all I am getting is a brownish discharge.
I am just wondering if anyone knows what this means, and if it could just be a short period or if its something else?

Could just be a shortish period. Caused by stress or illness. Could be a pseudo period that comes while pregnant. I would still take the test in a week or two.

Okay, thank you Craven.