What should I do when I've become unable to fulfill promises I made to myself in a previous period to give things to certain people, and now I don't remember all the promises?

Your statement, "If I get a job, I will give so-and-so such-and-such, and so-and-so such-and-such," it is recommended to fulfill it because it is an act of kindness to others. However, if you are unable to do so, there is no obligation upon you, because this phrasing is not one of the forms of a vow (nadhr).