What’s the deal? False positive?

I have been feeling nauseous and having a lot of headaches. Similar to what happened when I was pregnant with my son. I was in between birth control a for a couple weeks before switching to the Nuva ring. I had a very short period before starting the nuva ring. I decided to test just Incase... this came back almost immediately. The line was easier to see in person and did go all the way across. I took 3 other tests yesterday and all were negative. I also took one this morning and it was negative. Is this a false positive?