I haven't seen my period in May or June took a test it was negative July 23 it showed up lasted 4 days then ended according to this app my next period started

My period was absent may and June it showed up July 23 regular period last 4 days according to glow app my next period started August 20 around the 10th of August I spotted a few hours then stop I also been cramping bad for. Two days now I usually dont cramps I tested again and negative again felt cramping in my stomach left side this app said I ovulated last week what is going on can anyone explain it