4 weeks along and already have symptoms?? Could I be further along?

Took two positive pregnancy tests yesterday. Not sure how far along I really am as my last period was super light and lasted for 5 days but wondering if it was just implantation bleeding?? As I would only have a little spotting throughout the day. But if we do count that as a period I would be 4 weeks along and already having symptoms like cramping, headaches, aches, slight nausea, heartburn (which I never get). Is it possible that I’m actually further along than 4 weeks??