Whoa! That's tough! And I sure have been there. One idea:
Develop your own particular bedtime routine. The importance of routines in general for a toddler can not be over-emphasized. For some help with that (and reinforcement) look into books that involve Walfdrof education, Rudolf Steiner, and the like. Your Are Your Child's First Teacher is a must have book in my opinion, really.
Back to your nightime terror.
Run through the routine: wash hands, put on pajamas, brush teeth, read a book, sing a song, etc. What ever works for your family, but make it real specific and make sure you don't skip steps, ever. When it comes time for the actual putting to bed my suggestion is this: have a comfortable chair in the room with your child. You give a quick hug, and a bear to your child, then go and sit in the chair with a low light and begin to read (your book) to yourself. She will most likely come out of the bed on you. Don't speak to her, just put her back with one word: bedtime. Repeat over and over (and over) until she tires out and falls asleep, then you go and get some rest. The idea is not to reward her getting out of bed with comforting and hugs and all (there's a time for that in the daytime routine, just like there's a time for everything). You simply reinforce the 'it's bedtime' message by saying that one word and not giving her one more iota of attention past putting her in her bed. She'll scream and holler, but you'll know she's not physically hurt- you're there to ensure that. She's just reacting to your persistance, which she will eventually learn lasts longer than she does. That gives her something to count on, and children are looking for boundaries. Let her find the boundary, you don't have to punish her, just let her know the boundary doesn't move based on mood, emotion, holidays, or anyother factors. The routine is the routine, blame that when you are challenged by her.
"It's not time for cookies, silly." "It's time to wash up for dinner." "It's playtime!" "It's time to draw while Mommy makes dinner." Write the routine down somewhere and post it, then work that baby like it were law. The children will flourish, I promise.
This will take time. Be patient and do not give up! You will eventually teach her that bedtime means it's time to sleep. And that it's not a threatening activity or one where she'll be left alone to manage in the darkenss.
The best thing I can tell you about the whole thing is that it's a 'trend-thing'. It won't happen overnight, but slowly as part of a learning process. That's why having patience is so critical. And patience is hard to come by when you're stressed out and over-tired, believe me I know.
Comfort yourself by knowing that each child is different, and odds are the if/when you do have another, that child probably won't have the same issue. My first child was just like yours, and my second (born 2.5 years later) actually was instrumental in helping my older one go to bed at night, and to this day they share a room.
Deep breathing, pressing your hands at pressure points, anything you can do for yourself to maintain during those first few hard nights on the new routine is recommended. Just go real deep and find the patience to continue, and you will succeed. And then you will be soooo happy, and so will your family!
Best of luck! I hope this helps.