Is it wise to get a night guard from online? Will insurance pay for teeth damage from grinding?

[facebook101]

I lost my night guard. I am thinking my roommates cats got to it .

I grind my teeth pretty badly so I need a replacement one.

I am away at college so I can not go to my normal dentist.

The dentist I called at my college said that night guards start at $330 and can not give me the exact cost until I come in for a $96 appointment. I called my insurance and they said that night guards are not covered.

I would just go to the drug store and get one of the ones you boil but I was also using my night guard as a retainer so I am guessing the boil ones will not retain my teeth. (Am I wrong about this?)

So my two questions are,

1. Would getting one from an online lab work be fine? And if so, what lab do you recommend? And what thickness would you recommend?
2. I have worn my teeth down from the grinding. Is there anything my insurance might pay for in regards to getting this fixed? (They are very short now, to the point that you cannot see them when I am talking).

THANK YOU FOR ALL YOUR HELP.