I take Allegra-D twice a day, once in the morning and once at night, and my ex boyfriend is on it daily as well like that. Neither of us ever had any dreams like you are describing. Different people react differently to different medications, though, so I'm sure it's possible, especially if you started having the dreams right after beginning Allegra, that Allegra may have been a cause.

I just started taking Allegra-D a couple weeks ago and my sleep has been very disturbed. I've been trying not to take it within a few hours of going to bed.

Disturbed sleep IS listed as a possible side effect.

I would put money that your dream symptoms are from the "D" part of the Allegra-D. The D is for the decongestent part and I've noticed that when I use any OTC decongestents (e.g. sudafed) I can have some crazy dreams (although not as severe as what you are describing). Maybe if you can get away with no decongestent, try regular Allegra and see if your symptoms lesson. I didn't seem to have any problems on regular Allegra. Also, try to take your pill in the morning rather than right before bed.
Good luck.