2 positives and 2 negatives

Hi. I took a pregnancy test Thursday morning and it was positive. The second line was not solid but still there. I took another Thursday night. It was positive, the line still not solid though. I took another Friday morning and Saturday morning, but those were both negative. After the first one, I put it in the app and it estimated me to be 4 weeks and a couple days. This will be my first pregnancy after my miscarriage. I’m really confused and don’t know what that exactly means. What should I do?