occasional babysitter for a 1 and half years old Boy

Hello everyone, I am Federica and a happy mum of a beautiful boy, Liam. He's 19 months and goes to creche full time.
As you probably can imagine he gets sick a lot and unfortunately I cannot take days off work all the time.
so we are looking for a nice person, who can get to know our son and don't be a total stranger for when we need. I know that sometimes occasional work isn't ideal but we had situations where we had to change sitter 3 times in one week and it was a total disaster for Liam.
we would love someone nice, caring, and who loves kids and how to deal with tantrums over mum leaving.
we cannot wait to hear from you