Possibly pregnant

I have a five year old and have recently been experiencing a lot of the symptoms I had while pregnant with her. My last "period" only lasted a little over a day, and was very light. I've been getting light headed and dizzy a lot lately, have noticed an elevated heart rate (thanks Fitbit!), I get nauseous with certain smells and sometimes after just a few bites of food. I'm fatigued, and peeing all the time. However, I took a pregnancy test three days ago and it was negative. I feel like I felt early on in my pregnancy with my daughter, and I also tested negative once with her before testing positive, so I'm not sure what to think. My boyfriend wants me to wait a couple of weeks and test again, but I'm stressing myself out and that feels like it's too long to wait. Now would a really bad time to add a baby to our family (financial and relationship problems that were trying to work through), and I just want a definite answer. And if I'm not pregnant, why do I feel pregnant? I'm not sure what to do :/