Im not religious what so ever but i am a big believer in what is supposed to happen will happen. Even if you are on birth control if you are meant to get pregnant you will. I also think that you should only have as many children as you can support without having to rely on government aid. I'd wait. My daughters are almost 3 years apart and I feel constantly out of it. There is a saying that when you have two children you have the work of three. One baby is hard enough but throwing one into the mix right away is so much rougher. Plus the first year or so of a baby's life is so important for you to spend lots of time with the baby. You can always have more children later on.
wait until you are in labour LOL you must be having a great pregnancy! every pregnancy is different. with my first i was sick for the first 6 months, this one i have had constant scares since 14 weeks and i am due any day now. I know christians do not believe in sex before marriage and do not believe in contraception, you are just some trooper for not minding falling pregnant again! you can try natural contraception, ie not having sex at your most fertile time of the month, where it is just timing, not taking pills or using barrier methods. babies are costly which you will learn in due course, just hope you think about the risks in having another child ie not having much time with your first etc before it becomes too late. congratulations with your current pregnancy!
I think it's a bad decision to not want birth control. However, I have no religion and don't believe in leaving things in a God. We control our actions, and it's part of being responsible as human beings. If you can afford to have children immediately after you give birth it's your choice. But it WILL cause more stress on your body and can increase odds of complications. Not to mention you should enjoy time with your child while he's a child. If you get pregnant right after, you get sick, you're exhausted and it's just...blah. These are just of course my thoughts though. You'll do as you please.