Pregnant with a 1 year old and 3 year old

My son is about to turn 1 and my daughter will be three in a few months.

I just found out I'm pregnant, I was on the pill and we were being really careful and I woke up spewing a few days ago and just new :(

The reason I'm sad is because my partner has four with he's previous ex and told me to have a abortion he doesn't want anymore, he even went to the extreme and kicked me out because I was upset that if I went through with a abortion he wouldn't take some time off work to support me as I don't have anyone to help me with kids besides him but he said no he couldn't so I am heart broken!

Most my family are telling me I'm still young and three kids would be pushing it. I'm so depressed and don't know what to do, any advice please :(