How to use the expression "throw oneself into something"

Question

I have recently learned the expression "throw oneself into something", but I am kind of confused about how to use it in daily conversation. Could anyone explain me this, with some examples?

For example,

I've thrown myself into learning English.

Is this sentence grammatically correct? If yes, then what does it exactly mean?

Answer 1

Yes, "to throw oneself into" is a standard idiom.

• cambridge.org: to do something ​actively and ​enthusiastically
• thefreedictionary.com: to enter into or join something eagerly and wholeheartedly
• dictionary.com: to engage in with energy or enthusiasm (definition 53)
• oxforddictionaries.com: start to do (something) with enthusiasm and vigour

Answer 2

To

throw oneself into something

is to work on or study or become involved in something without holding back or reservation.

I've thrown myself into the deep end ( of the pool )

is a possible metaphor (unless you really did go into the deep end of a pool) to say your situation is all or nothing, sink or swim.