YOU SAID:

i want to say thank you for all the things you've done for me

INTO JAPANESE

私がしてくれたことすべてに感謝したい

BACK INTO ENGLISH

I would like to thank all the things I did for you

INTO JAPANESE

私があなたのためにしたことすべてに感謝したいです

BACK INTO ENGLISH

I would like to thank all the things I did for you