Prego

Angel

So today I make 19 weeks n 3 which mean I am 5 months the doctors gave me a pregnancy book n it say 5 months is week 17-20 n week 21-24 is 6 months is this correct because my due date feb 3 , 2021 n I am starting to think something off either I am due early then feb or the doctors off n lying Somebody help me understand ima first time mom n I think since I am 5 months I only have 4 left but this book confusing me