Is my new puppy going to be alright? Does this sound like parvo or home-sickness?

Hello. Yesterday, I adopted a black lab from a man who said he rescued her from an older couple who wanted to take her to the pound because they couldn't handle a puppy. He said she doesn't have shots his knowledge. She is about 3 months old. We'll be getting her to he vet for shots on Monday or Tuesday. She is a bubbly little girl. Goes pee outside, poo, she hasn't quite learned yet. Yesterday night my dad gave her a few bits of steak (I told him not to so please no negative comments) because our old dog loved steak scraps. They were big enough for her to swallow, obviously. She also was given a puppy rawhide for teething from the pet store, and she is eating the same food as she was at her old home. She woke me up at 5 this morning, throwing up the meat on the bed. She was trying to get off but she's too little for that yet. I moved out on the couch with her. She fell asleep, and woke up a little later. She wanted out, and peed. Then, I guess I brought her inside too soon, because she pood in the room that we were sleeping in before. She fell asleep after I cleaned it up, despite wanting to play. Then, she woke up twice, got off the couch and threw up clear. Let me add that her poo was solid, no blood, no worms. And there's been no blood in her throw up. After the last time she threw up, she laid down and wanted to stay there and sleep. She's been laying around all day. When I take her outside, I have to pick her up off the couch or wherever she's sleeping because she doesn't know what "Do you wanna go outside?!" means yet, so she just stares at me. When I let her back in, she darts back to her sleeping place and watches for me to come cuddle with her, and when I do, she lays her little head down. We've taken her outside a few times today. Two of the times, she pood a jet stream of liquid that looked like yellowish water, no blood, followed by a little bit of gooey diarrhea. After pooing, she would jump around a lot more like a happy puppy would. She also walked around my yard with me, running and sniffing everywhere. When she got back inside, she went back to sleep. She's been sleeping literally all day besides going outside. Earlier, my dad and I got her to wake up because we wanted to see how she was doing. We pointed out my hamster, running around in its ball. She jumped off the bed, ears up, going to investigate and paw at it. I just let her outside again, and when she came inside, she was perky on my bed for awhile with her head and ears up gnawing on her leash, but then she went to sleep again. She has also been drinking a decent amount today, but refusing to eat everything offered. Could this be parvo? I'm so scared. I love this little girl already. We think it might just be her being home-sick, getting used to a new place, since her old home had multiple dogs. She's the only dog here. ): Please help me. Thank you.<3