Input would be awesome plan B

Hello, so I have 4 kids and my youngest is 5 months .. I’m breast feeding and I haven’t gotten my period back. My husband and I had a ton of “fun time” and the next day I felt my ovulation cramping I took an ovulation test and it was positive. I went and took a plan B to prevent being pregnant again so soon. But It’s been 9 days and I haven’t gotten a period. Anyone ever have this happen? Any thoughts? I took a pregnancy test yesterday and it was negative. (8 days past positive ovulation test)

No judgement please just supportive input. We love being parents but just want to enjoy our 5 month old a little longer before another one.