Eee... I think that you will have to recut it, unfortunately. You can probably leave the lights and the tinsel on, if you do it carefully--but anything that could break if it falls off should definitely be taken off before you recut.

I usually cut off about 3". You can also try using warmer water. I read something recently that suggests you use very warm water always when watering the tree as it will be taken up more easily.

I was talking to the guy who has a cut your own place here. In this area at least (Dayton) the soil is alkaline and Firs like acid soils, so they aren't grown. Any fir you buy has been trucked in, and could have been cut well....as long ago as Oct! At least that's what the Mainiacs (folks from Maine ; ) ) who I knew told me.

I always try to cut my own. Firs, balsam and Frasier, tend not to hold their needles as well as others. In years with drought, even cut your own may lose their needles more quickly than usual. Although it won't help you now, and you may already know it, one rule of thumb is to bend the needles in your fingers. If they are brittle, or if they pull out easily, try finding another tree as these are not as fresh as they could be.