You don't wake up one morning going "I know some java...lemme learn Dynamo and S3 and SQS while learning dependency injection and Spring while figuring out what this SQL thing is about on Postgres...or should I use MySQL? Oh and there's Maven and Puppet and all the deployment tools...
That would be totally insane.
Look at frontend the same way. If you're trying to learn react and babel and ES6 and webpack and eslint and flow/typescript and NPM/Yarn and Node while looking into Service workers and websockets at the same time as reading a book on Functional programming, yeah, that's overwhelming.
Pick one thing and a time and go for it. If you're a backend developer and getting overwhelmed by frontend, it's because you're attacking it from a "Frontend is an atomic small thing" perspective, as opposed to being an ecosystem just like on the backend. And that won't work.