Could I be pregnant ?

I have been having so many symptoms. Back aches, constipated, naseous, super sore breasts and nipple so sensitive and sore. I took a dollar store test Friday and it was negative. I bought an early detection first response and took it today and it was a no again. My periods have been wonky since u miscarriage in May. Anywhere from on time to 2 weeks late. Technically I should be getting it now but I Duno if it's gonna be late again or what. Opinions please.