please help my puppy doesnt eat&drink..+ transparent jelly like in poop

i have a 2 month old puppy unlike his brother his not much interested with food,, when i feed them the other pup will always be excited to eat but when it comes to him he eat his food maybe half of it then eat again when he felt like it or sometimes he dont.,,just this morning when im feeding them i put his food in his bowl and slept again because iwasnt also feeling well so i took a rest.. thinking that he would eat it after i left it there but he didnt.. so i throw out the food and gave him a new one for his lunch but he didnt even take a bite nor drink water.,. he was just sleeping on his crate the whole time but when i let him out of his crate he was still playful but this evening he still doesnt ate a thing and he started to poop with a jelly like on it then he was still playful and defecate again this time a jelly likeish without poop but no blood in it.,so i started to become worried because he still doesn't eat or drink and started throwing up.. so i tried to hand feed him but he would just spit it out though i manage to make him drink by syringe w/o needle of course..,but still throwing up and im afraid that he would get dehydrated or hypoglycemia for not taking food,.i will definitely take him to vet tomorrow but i also i wanna know if there is something or aid i could do tonight for him.,?? thank u for those who will answer.,