Lingering miscarrige or new pregnancy?

I found out on christmas I was pregnant. 😪 Unfortunately around Jan 16, I miscarried. My betas never made it past 575. I went in for a repeat beta 4 days later on Jan 20th to make sure levels were dropping and they were 137. I figured with how quickly they were dropping that by now they had reached 0 and with our first miscarriage my levels dropped to 0 in a week. So, I wanted to take a test this morning to see if it was negative yet but noticed I still have a vvfl. Is this lingering hcg from the miscarriage or is it even possible to have a back to back pregnancy after a miscarriage?