The verbs are all over the place in this one.
Since I prefer past-tense narration (present-tense narration usually feels artificial/contrived to me), I’m choosing that.
Change you’ve lost to you lost.
Change discover to discovered.
The phrase written by yourself is awkward (and passive voice, for those who care about such things) and just the slightest bit grammatically incorrect. If you want to emphasize who wrote it, and perhaps that the POV character doesn’t remember writing it, try written in your own hand instead. Otherwise, just written by you works fine.
Oh, yeah — get rid of the unnecessary (but at least with the right number of dots — yay!)ellipsis at the end, and replace it with a period.
You woke up to be told by everyone around you that you lost all your memories in a car crash. Years later, you discovered a journal written in your own hand that tells a different story.
(Some of you may be expecting me to make a joke of some kind about the subject matter of this example: car crash, amnesia, yadda yadda… But I’ve been re-watching the first season of Fringe lately — my twin’s idea, actually — and I’m just not in the mood, so I won’t. *mutters something about summer camp and ‘You’re an evil man, Mr. Goldsman’*)