Flashing a rom does that- deletes any locally (internal memory) stored applications and contacts. if your phone was syncing properly, your apps should be remembered and auto-downloaded by the market. Your contacts though, are a different story.
What you can do for contacts, well there are a few options.
You can go to your contacts, go to settings and export the list to your sd card, to be imported later (say if you flash anotherr rom, go back to stock, or when/if you decide to go to gingerbread)
You can log on to your gmail account, preferably on your computer, and edit your gmail account to include your contacts. This way, when you sign in to gmail after first flashing the ROM, they will all be auto-added.
Or, and Im not experienced with this, log in to your verizon account sync online and back them up manually BEFORE flashing, and then sync them afterwords.
Either way you will need to add all those contacts manually at this point, unless I am mistaken. I flash between stock, fission, and d2 roms constantly and I always have to ask people for their numbers over and over again since I dont do those methods. Exporting to the sd card can be shoddy at times, just so you know. I would recommend editing your gmail contacts AND doing the account sync thru a PC just to be sure