Pregnant with 8 Month Old

I just found out I am pregnant! My son just turned 8 months last week and I am completely shocked! I am so terrified because I am only 22 years old! Ladies around my age has this happened to you? What advice can you give me? I haven't told my boyfriend yet but I know he will be happy but I am just scared to deal with 2 kids. My son will be almost 1 1/2 when the baby is due but I am still nervous!!!