Are you testing with morning urine when the pregnancy hormone is the strongest?
Symptoms don't tell you whether you are pregnant or not and can be pretty unreliable since they can also be symptoms of many other things. You were late last month as well as this month, so I think it's more than likely your cycles are a bit messed up. Many things can cause this. Since you took the test when you were already late, it's unlikely you are pregnant as it would show up by now if you were. If in another week or so you still haven't had your period, then go see your doctor.