Two years since miscarriage.......bfp.....advice needed

I had a miscarriage about two years ago, I was pretty sure it wouldn’t happen for us as we have three beautiful children. I’ve been changing my diet due to possible thyroid issues and today I felt super sick. On a whim at 4:30pm I took a test I glanced at the one minute mark and said I was dumb it’s negative and then just 3 minutes later bam there it was, I know I should be so excited but I cried for a solid 30 minutes out of fear. Based on my last period I’d be about 6 weeks, however I’m a pretty irregular person so I don’t know how accurate that it. How do you get through the fear of loss?!