Need some support

I have a 3 month old and I just took a pregnancy test since I still haven't gotten my period and it was positive. My first reaction was shock, scared and now I'm an emotional mess crying in bed. I told my SO that it was positive and he said that whatever my decision would be about it he is behind me. I never had an abortion or miscarriage and I can't even think of losing something so precious as a child. I afraid of not being financially ready for another baby since I have a child starting college in 2 months. Also I will feel bad that my 3 month old will not get the time and attention he deserves cause a new baby will be coming. Please help me weigh the pros and cons. What should I do? Also I go back to work in September and would only go back for 4 months and have to leave again. I don't think that wil go over well with them either.