By now you most likely can tell the difference between her crys. If it is just her annoyed cry then your going to have to let her cry. She needs to teach herself to fall asleep. This is going to be very hard on you. Very hard. If the baby doesn't learn that bed time is for sleeping you are going to have an even harder time when the baby get older and mobil. Eventually her crying will not be as intense or last as long. Then she will eventually learn to entertain herself until she falls asleep. My best wishes go out to you. Hold strong.
Is she colic Nikki?
Have you tried giving her a little gripe water, or a baby massage? Usually, when a baby is screaming, it's because something is causing her pain...perhaps there's some gas trapped in her belly and you need to try to burp her a little longer. There's also the possibility that she's teething - I know she's only 3 months old, but it happens...watch for flushed cheeks and drooling.
Keep a damp cloth in a baggy in the freezer and let her chew on it when she gets cranky. You can give her some baby Tylenol, but don't use it as a crutch - you don't want to be dosing your baby. It probably wouldn't hurt to get her ears checked as well...often, when babies teeth, they develop painful ear infections. Teething is a tough time...but this too, shall pass...
Shes going to be 4 months old on the 17th and she fights her sleep alot even during the day but at night she hates to go to bed but im trying to change that!! And yes i think she is starting to teeth cause her cheeks are rosie and she is drooling more than usual and she has her fingers in her mouth constantly
Adding to this, sometimes at night they can actually be hungry, that is if you have tried everything else and they are still screaming. Try feeding them more that time of night. (I know someone who had that specific problem with her baby)