i think sleep changes, first of all, are really normal. very annoying and scary, but normal. so don't go the "is something wrong?" route in your mind because you will drive yourself nuts. try to focus on this being very annoying. :) BTW my kids are 3.5 yr, and 22 mos, and they have both gone through extended periods of sleep disturbance just like what you are describing.
first of all consider making bed time much earlier! i know this may seem counter-intuitive, but VERY often what will happen is that the window for calm sleep time passes and the babies go into overdrive. this still happens a lot with my kids. you'll notice things like the baby getting excessively wierdly 'happy' and 'chirpy', running around, being disorganized, going from one thing to the next fast, having a tantrum, etc. so i would say start looking for signs of her being tired, even the littlest bit of eye rubbing, staring into space, slowing down, will often mean she's ready to go to bed.
make the bed time routine more drawn out, a little slower, and very low key; make sure the lights are low, the bath is warm and quiet and not too playful, when you read the books do so in a dimly lit room; if her room doesn't have a dimmer switch, put one in. it's very easy. or don't use the overhead light, use a very low wattage table lamp.
now also, though i am STRONGLY AGAINST excessive crying it out, sometimes the babies may need just 4 or 5 minutes of crying to break the overtired spell. you could do the bed time routine, let her cry for like 5 minutes (stay close by the door), and then take her out just to read one more story and rock a bit more, then put her back in. if she cries again, same thing. i think it's really important for your approach to be more gentle than assertive; consistency with kindness. and safety.
for yourself try not to panic or get anxious about this. she will feed off your energy and get more wound up. another thing we have done here when my daughter is going through the main things that cause her to stay up, which are, A) langauge and milestone development and B) teething, is to just set up the living room as a safe enviornment, totally baby proofed, and my husband will camp out on the floor with her. make a bed on the floor of blankets, put the lights VERY low, and put on a long, quiet movie. she will usually sit down and watch it while he dozes off beside her, and she will go to sleep. they do this in the living room with baby gates. the movies i reccommend are;
The old version of "Charlotte's Web" from 1973, you can get it at Target, also "THe Many Adventures of Winnie the Pooh" this is also an old one, and the original "Lady and the Tramp." also old. these older classics are done with MUCH less hectic action and are very peaceful and mezmerizing with beautiful music. my daughter loves them.
lastly, try to remember that it won't last. she'll probably self correct sooner than later. i know it's crazy making but it will likely happen again, it is a phase. also put yourself to bed earlier if possible.