I'm really sorry to hear this...
I hate to jump to this so quickly, but due to the fact that your trainer commented on how high strung he is AND the fact he scares himself just being turned out... would you consider selling him and using the money to buy another horse?
Honestly in this instance where you are a new rider (first horse), and your trainer even commented on how jittery the horse is, this does NOT sound like a good match to me. Just sounds like a wreck waiting to happen, or a major risk of ruining your confidence. Perhaps you could even find an experienced rider with an older, quieter horse who would take him in part trade or something.
Otherwise, maybe you could consider sending him to a professional trainer for a while?
On the bright side, horse prices in most parts of the states are low. If you can sell him and then get a part time job as well, you can probably save up to buy a decent, broke horse for quite cheap depending where you are.
Really sorry to hear :(