Lost Score

So I've been working on a piece for a good while now, I had several minutes' worth of music in the score, and I saved it last night (It's a public score and automatically updates the online version anytime I click to save) it told me there was another score with the exact same name (never had this happen before) and asked me to merge the files, I clicked okay and it merged the files. Everything I had done over the past several weeks was then erased from the score and it went back to how it was 4 months ago, on the website the audio plays the correct (up-to-date) music, but the sheet music itself is very old. I have no idea how to fix this or if it's even a possibility, I'm just very confused right now.