I immersed myself in my work and hobbies to stay strong and positive.
I gave myself up entirely to my work and hobbies so that I could stay strong and positive.
I spent all my time on my work and hobbies so that I could stay strong and positive.
1) I immersed myself in my work and hobbies to stay strong and positive.
immerse myself in...「…に没頭する、集中する」
to stay strong and positive:「~ために」というto不定詞で、「強く前向きでいるために」
2)I gave myself up entirely to my work and hobbies so that I could stay strong and positive.
give myself up entirely to...「…に没頭する」
I...so that I could ---「---するために、…する」
3)I spent all my time on my work and hobbies so that I could stay strong and positive.
I spend A on B.「AをBに」費やす
all my time「自分の全ての時間」
→all my lifeだと、「全人生」となります。I'll spend all my life loving you.「一生、あなたを愛し続けるわ」
I devoted myself to my work/hobbies. とも言うことができます。
devote「捧げる」
色々なバリエーションを使ってみて下さいね!