just want to burst out my feeling

I don't think you've done anything wrong just by asking for the money you lent. Just as long as you said it in a nice way and not in a degrading way. Sometimes, when it comes to families, lending money is easy but expecting for any payback is quite difficult. Unless it's quite a big amount or something. Anyway, try talking to your husband again but make the conversation light so as not to initiate any further conflict. But if worse comes to worst and your sister-in-law never got the chance to pay you back, then just let it go but learn from it.

Nope I dont think it is a mistake of yours. I am only wondering why you had to ask her about your money. You know it sure can happen that she is not able to pay you cause of any reason,but she could call you and tell ya to dont be mad something happend and she will pay ya from the next salary

Nothing is wrong in asking for your money back, if you gave her a reasonable time, and she made a promise that should would pay it back on a specific date than its her duty to do so. So since she didn't you have the right to ask for whats rightfully yours. This is why I stopped lending money to friends and family. I would give them money not as a loan, but to loan a family member money especially I would not do. So many troubles can come because of this!

If she won't pay you, then that's okay. At least now you know she cannot easily be trusted in terms of you lending money. All you can do is try not to make the same mistake again.