Had a Worrying Mix-Up with My Drink Order

Assalamu alaikum. As a Muslim, I recently faced a situation I'm reflecting on and would appreciate some insight. At an event, I asked for a mocktail, but I think I was mistakenly given a cocktail. I started drinking it, believing it was alcohol-free. After a few sips, I caught a strong taste and recalled the server mentioning 'mule' instead of 'tea,' which made me doubt-but I didn't stop right away because I thought it could still be a non-alcoholic version (I've had those before). I took a couple more sips while uncertain, but just felt uneasy-so I finally set it aside. I didn't finish it (around 80% was left). From an Islamic standpoint, how is this viewed-particularly the part where I continued drinking briefly after starting to suspect something wasn't right? I'm feeling really guilty and wish I had stopped immediately.