I’ve always wanted to go on one, but unfortunately my church doesn’t do them. I’ve thought about joining the peace corps, but I think 2 years in a foreign country might be too much for me. So does anyone know any organizations or whatever that I can do a mission trip through? Any suggestions would be great! Thank you! =)

I recommend the Christian Appalachian Project. You can decide how long your "mission" will be. They minister to the poor in the hills of Eastern Kentucky. When you see how poor these folks are, you think you’re in India, not the USA!.
I’m an alumnus of 2 summer sessions there. In fact, I was a member of the original construction crew that built the lodge at their summer recreation camp. A most gratifying experience.