I had my last "normal" period the second week of November around the 11, had light bleeding around November 30 or December 1 that lasted maybe 3 days at the most. If that was my period, since my cycle is usually normal, I believe I should've had my next period last weekend. I've been cramping on and off for a few weeks but they started getting more intense during the last week. Throughout this month I've had headaches, heartburn, and have been irritable and restless at times which isn't normal for me. When I figured I was getting my period last weekend and even throughout this week I would go to the bathroom and expect it to be there but there hasn't been a trace of it. I have a 4 year old and completely missed my period and didn't take a test until I was nearly two weeks late and tested positive. I don't remember much from that early in my pregnancy the first time, but I do remember feeling pressure in my lower abdomen as well as a more constant cramping feeling in the middle lower area of my abdomen and also remember it feeling hard when I put pressure on it or tried to lay on my stomach. I didn't think much of anything until maybe 2-3 days ago when I started to notice somewhat similar feelings in my lower abdomen in the last couple of days. There are a few unusual sensations and feelings in that area and feel like there is pressure inside where my uterus is and around where I know my cervix is as well. I probably wouldn't notice it if I hadn't felt some of the same symptoms early during my first pregnancy. I'm not on any birth control or medication, and have had unprotected intercourse throughout last month and this one. I thought it was too early to take a test, but took one since my boyfriend asked me to yesterday just to ease his mind and it came up negative, but I'm still not completely convinced it was right and think it still might be too early to tell, but I'm aware I could still possibly get my period too. Now that I've compared these symptoms to my first pregnancy and remember certain feelings really similar to this I really need a second opinion so I can either put my mind at ease or start mentally preparing to possibly having another baby.

You are correct, it was totally too early to take the test. You have to wait till you are about two weeks late to properly test. And then have to use the first urine of the morning.
It can be pregnancy, infection, STD or a number of things. At this point there is no way to tell.

I will assume you two are trying to have another child ?