I just found out I’m pregnant with my second 😕

So just like the title says, I just found out that I’m pregnant with my second baby. My first one is 16 months currently. I don’t know how to feel.. I told my boyfriend, who is also the father of the first, and he seems alright with the news. We’re 22 and plan on going to back to school. He wants to be a truck driver and I’m going back to be a nurse. Y’all I don’t even know how many weeks I am.. I was on birth control so I really don’t know my last cycle. I feel so scared and sad. I’m not sure how to feel... Any advice?