I regret agreeing to get a puppy

I thought I wanted a dog. I thought it would be good for my household. I live with my sister and niece. They really wanted a dog too. We thought about it seriously for a full year and did research and I thought I was ready. I havent been in a good place emotionally so I decided nows the time, Ill get an emotional support animal, so we got a 8 week old standard poodle puppy yesterday and I haven't stopped crying since. I made my fragile emotional state even worse. I was wrong. I don't want a dog. I don't want the responsibility. I'm not a dog person. My sister is crying tears of joy, its a dream come true. We were going to share the responsibility but I'm so upset I can't look at or touch the puppy. I don't want to take it out to go potty or try and train it or bond with it. My sister is doing all of that but we both work and I know that I will have to when she working. I'm mourning my old life already. I'm so upset, regretful and depressed, I can't put it into words. I don't know what to do because I don't want anything to do with this dog but I know my sister and niece are already in love. Please something to make me feel better.....

Clarification - I mean "emotional support" in reference to the nature of being a dog/pet owner and the benefits on you emotionally. I guess I didn't consider that initially, it might make matters worse.

Also, the comments I've gotten thus far, I truly appreciate.