Why do I doubt?

Our car has been giving us problems for the last week or so. When we'd stop at a light or stop sign, and then go again, our car wouldn't want to go immediately. It would rev the engine, and then finally catch the gears and go. We decided to take it into the shop before taking it on about 8 hours of driving over the weekend (split between various trips). I called the mechanic that we used before (the a/c went out because some trailer drove over something and threw a metal thing into my engine and damaged the a/c. I saw it coming but could do nothing to avoid it.) They said that he could squeeze me in if I was there right at 2 so they could diagnose it. But if something needed to be ordered, it wouldn't be fixed for a couple of days. I said, "Ok, I'll try my best to be there." In my mind, I'm thinking, "That's 2pm, in the middle of the worst of the heat. (It was in the mid-90s yesterday.) It's less than a mile so I could walk home, but poor Little Miss! She'd be miserable!" But worse than that, I was thinking about being without a car for a couple of days. My in-laws are coming, Hubby has 2 away games (Thurs and Fri), we're going to my dad's concert after the Thurs game (it's at the same church! How cool is that?!), and my niece's birthday party is Saturday and I'm making the cake. That's a lot to do without a car. I looked at renting one, but it was $90 for Thurs-Sat, on top of whatever the car is going to cost. I was very stressed out, thinking, "How are we ever going to pay for this?" I have a pity party and ask God why we are going through this yet again! Then Hubby emailed me. Someone is going to let us borrow their car, and can I call them since he's in class. So I call, and she offers to pick me up at the mechanic and take me home to get their car. Yeah! So she picks me up and on the way there, she says she'll just let us borrow the one she's driving now since she won't need it over the weekend. She just has to clean it out at her house. So we cleaned it out and we were about to go, and she said, "Oh, do you have room in your freezer? Do you want some meat?" "Sure!! I'll make room!" So she gives me steaks, pork chops, and sausage! 

I drove home, thinking, "God, why did I doubt you? I get so stressed out about the money, but you always come through and always provide for our needs. We have a car to borrow and some nice meat! Thank you!"

It gets better. I get home and decided to call the mechanic to let him know that there was a puddle of stuff where the car had been parked. (He asked if it was leaking, and I said I didn't know, that I hadn't looked.) The woman who answered the phone (who knows where Spangdahlem and Bitburg are, as she was a military brat who lived in Germany!! We talked for about 10 minutes about Germany when I dropped off the car) told me that they had already figured out that it was leaking, and it was fixed! What?!?! A hose was leaking, so they replaced it and replenished the transmission fluid, and we were good to go. Yeah! And the cost was not too bad, especially considering that they squeezed me in for a rush job. So Hubby went to pick up the car when his coworker brought him home.

So back to my original question, why do I doubt? Why do I think that God isn't going to take care of us? How many times does He have to teach me until I finally will rely on Him when things seem impossible? You'd think I'd have learned that lesson very well by now. But I want to know how He's going to do it, and how quickly it'll be over. Someday, I'll learn to just wait on Him. It's funny, when I was a missionary, I think it was easier to just wait on Him. I've been off the field for a month, and already it's harder. How strange.