Boy, I'm a Trainwreck

Let me start this by saying that I am an articulate, fairly educated late 20's woman who is in a stable long term relationship and is a loving (albeit frazzled) mother of a toddler.
I had to go to jail for a weekend (car insurance lapsed and I ended up unknowingly driving on suspended) and wasn't able to take my birth control while I was in the big house. 
Two weeks later, I found out I am pregnant. I'm an (unpaid) competitive horseback rider, we are a single income house, and I am at a loss of what to do. I want to go back to college for sustainable agriculture. I don't know how that would pan out with two kids. I'm not even sure if this is my search for insight or just a vent.