If you are suggesting you physically went back in time such that you could change events rather than just had a vivid memory, I would suggest that was a little delusional (unless you could prove it).
How could you prove you went back in time and changed past events if the present already represents those changes as if they always were?
Taking mementos proves very little other than a well preserved antique. You'd have to do a Bill & Ted and bring someone back with you to vouch for it -- and then they get locked up for being a schizophrenic with identity based delusions of grandeur.
Why would you want to prove it anyway? If the changes made were for the better - the knowing of that deed would be enough - but then, that memory would fade as you adjusted to the new existence created. Also, if you change things previously wrong, then the present would offer no reason to go back and alter anything - effectively undoing any timeline in which time travel had purpose - so you wouldn't have, would you? - or nothing can be changed.