Short light 4 day period and still spotting 5 days later

Karen
I'm so uneasy about what's going on. I've had dysplaysia before and I'm hoping that this isn't something serious. I never have short periods. They're usually 7-8 days and heavy. This past one was 4days and light and I've been spotting for the past five days following the end of my period... Once again, not normal at all. I only had sex once last month and it was the day after my fertile window ended, 23rd. Started bleeding on the third. Any ideas what this could be? Google always tells me I'm either pregnant or dying. 😒