How to get over it? You're 18, live a little first.
There is plenty of time in the future for you to decide what exactly you want to do to become a parent. There are options to have your own genetic children or adopt, that's all up to you. The greatest thing you could do for your future child is to get a good education and have a great career so one day you can support them with what they need.
That is one reason I'm 31, my gf is 27, and we still don't plan on having a child for another decade. People do it all the time when they're not financially or emotionally prepared and the child is the one to suffer for it. I don't believe in having a spoiled brat but I do believe a child should never have a need that goes unfulfilled.
My advice is to focus on yourself first.