yeah, its a weird day and you kinda have to destroy it and rebuild it from the ground up into your own personal (in regards to you and your partner's relationship) celebration. the concept and current iteration of Valentine's Day is something we're both staunch opponents of, but at the same time 1) i love spoiling the people i care about and 2) she loves flowers. so i had some local florists deliver a few bouquets to her (and a few close coworkers of ours) at work as a surprise, and then after work instead of wasting time cooking we just grabbed some burgers to go from the local pub, came home, watched Clueless and Bram Stoker's Dracula and then fucked with some of our new toys. most of this was discussed and decided beforehand, so we were both on the same level re: expectations for the night.
it was your first V-Day in a new relationship and on top of that, a bunch of shit you couldnt really have any control over went down before you even got home. she definitely reacted in a way that wasnt super healthy and i know how you feel because ive had relationships like that in the past. but given the circumstances, you have to decide if you think those specific conditions are a result of a single bad moment that you can talk about and work through, coming to an understanding together, or is indicative of what the future holds for the both of you. could be that her excitement about what is generally regarded by the populace as a "special and romantic day" coupled it being a watermark in a new relationship didnt meet her predetermined and perhaps excessive expectations, which can be understandable but still shitty, or it could be shes going to be a person who will never appreciate whats done for her and is impossible to please... or something inbetween. thats up to you to decide.