really concerned

Katherine • mama of 2 || 20 years old

SO and I just started trying this month, we started a couple days before my period was estimated to be due, and it did not show up, now a week later it still isnt here and this is the latest it typically would be. Tests say negative (i assume it would be too early either way) and I have had symptoms such as tightness or pressure in my uterus area and nausea. Now this is what i am concerned about, all day today I have had sharp pains in my lower abdomen/uterus area along with the tightness feeling. I am really concerned because that does not happen with AF for me and if i am pregnant it makes me nervous, what should I do? or what could it be?