It may well be that your manager has over-reached his authority in some areas of the work he has asked you to do, so you need to protect yourself for the future.

From now on, Izabella, please keep a diary of the things you are asked to do. Keep every piece of paper to do with projects, including little notes - no matter how insignificant.   You can be sure that your manager is not keep a record, so your record will stand against his word.

If you have to seek approval for something, then I suggest you do it in writing.  If you manager gives verbal approval to your written memo ask him to just sign it approved.  If he asks why you need this authorization, then just give him your biggest smile and say you don't want there to be any misunderstandings in the future.  

Good luck.

Raindance