possible pregnancy right after mc

I miscarried on Sunday may 21 I bled until Thursday may 25th my hcg levels were test the Friday before I mc and they were 11 then the Sunday it started they were a 9 on Tuesday may 23 they were a 9 still yesterday I went in for more blood work and they are now a 18. Also on Wednesday may 31 I started bleeding again and it lasted one day but was light is it possible this could be a different pregnancy that just started or what is it? They are doing a sono to check for etopic on Monday but said they don't think that's what it is because I'm not in pain and stopped bleeding.