HELP!

72 days ago I hired a stud for one of my Yorkies and another female winked

at him and he got her, (I didn't know she was in heat) I took & put her away. The Stud left the nest day. 9 days later MY male (who I thought was too young) got her 3 times that I know of. Anyway, 62 days after the Stud got her she had 3 puppies (which was on 4-19) Then to my surprize

TODAY, 9 days later she has another puppy

. Could this of really happened, Getting pregnant from 2 different males and delivering each one separately? HELP ME PLEASE!