Feeling odd, am I pregnant or paranoid?

Ladies, how did y’all first know that y’all were pregnant? Before taking any test or going and seeing a doctor. For the past few weeks, my lower stomach has been bubbly and felt tight, I haven’t had my period in a good while (I have the Nexplanon in my arm so that might explain it but usually I would have already had my period), I have been more tired than usual, and I have noticed a change in my discharge. Should I be worried or am I just freaking out for nothing?