Is There a Chance

My SO and I recently decided to TTC and it's been a pain in the rear waiting to find out if AF would show or not. my period ussually starts the 5th of every month. Today I started bleeding but not the normal. It was spotty and brownish red color then turned into a medium flow (enough for 1 tampon) with mild lower stomach cramps. I have been having weird sysptoms: tired a lot, using bathroom more, cravings, lower back soreness, nuesa and sore boobs. My period is normally very heavy and I get extremely sick when it starts which oddly I'm not. 
Is there a chance I could still be pregnant or not? Just the thought of AF showing up makes me feel horrible and like I let my SO down :(