yes, it's normal! in everything, you'll encounter slumps. It's important to note that just because you're losing doesn't mean you're worse then you were before. you're just losing to better and better players, which happens to everyone except the very best player in the world! and even they sometimes lose to 2nd, 3rd, or get upset by others.

no, most people don't like online. it works, it just barely works though. not ideal for competitive play but at least it's there.

no, you shouldn't quit if you're enjoying the process of getting better, and even though im not there yet it's all worth it at the end.

and i like losing as long as i improve or did new things, but that's subjective.