Prayer and Insight Needed!!!

Well since I went on my first missions trip to Guyana a little under 3 years ago now I've been wanting to go on another trip for longer and to do medical stuff. In the past I've always made excuses of why not to go, money, family, and much more but really it was because I was scared. I'm still terrified, but this summer I have decided that I am going to go! I originally was going to go with an Anatomy Professor to Guatamala and it was the "perfect" trip! But because of some unfortounate event's he is no longer going. I then began looking for different trips, but it seemed for a moment that maybe it wasn't going to work. I was upset, but content. However, I kept looking and now there are so many opportunities and I don't know what one is right for me if any! Here are my choices:
1) I have an opportunity to go to Thailand for 5 weeks backpacking around the country doing some medical missions as well as helping in orphanages and working with a place that helps former prostitues learn life skills. This is a decent priced trip, $3200, with amazing people and what will be doing there sounds great! Plus it goes from May till the middle of June so that still gives me time to go home and work! This trip is a definite that I can be on...if I tell them I'm going, I'm going
2) I have also found a trip with Pioneers missions to West Africa. This trip is 6 weeks long and very expensive, $5750. It is medically based and sounds really neat. We would mainly stay in one place and work with missionaries there. This trip runs from June to July, so I would still be able to come home and work and catch up with people. I am currently in the process of applying for this trip and it is not like the Thailand trip wheter I can definitly go on it or not.
3) My third option that just came about tonight is possibly going by myself to Guatamala and helping out a missionary that our church supports (Kathi Archer) do slight medical stuff possibly one day a week if that, so not nearly as much as the other 2, I can stay as short or as long as I want up to 3 months. I have to fill out an application for this as well. It will probably end up being the cheapest out of all three. It's 150/month for room and bored plus travel expenses and anything else that I would need. I can choose when I want to go, but again very little medical experience.

That's it for now, possibly another Africa trip with church, but that was just an idea thrown around with no real planning or anything to it. I just don't know what to do. There has definitly been a lot of prayer about a trip, but I still don't know. At first I was totally turned off to Thailand, but then after talking to people about it I really enjoy the idea. Africa sounds AMAZING, but it is very expensive. I know that if that's where I'm suppose to be God will provide but I am a worrier! And Guatamala would be totally fun and such a great experience, but I really wanted medical and although I will have some, it's not that much medically based and it doesn't involve orphange ministry which is another big thing. It's always been my dream to run or at least work in an orphanage.

So if you could pray and if anyone has any suggestions or idea's that would be greatly appreciated!

Thanks! and I will keep you updated