Implantation! Help!!

never ever posted on these sights before but so confused! My periods are irregular! But I had sex for the last time 6 days ago and today I have had brown blood not a single thing since this afternoon! According to my glow app I'm on day 3 of ovulation? And period should be due in 14 days? Could I be pregnant?? It's hard to track as each cycle varies some 20 odd days, some 30 sime can be completely off the chart 😖