I hate to be the bearer of bad news but this is what were facing.. Since you accessed and wrote the draft through your web browser, then theres no physical copy of the draft we could restore. ( Such as if you were using the outlook 2013 mail program, or the free thunderbird or windows live mail program )
With that being said, it appears what happened was there was an issue with your browsers cookies.. Specifically the login cookie. When it signed you out of hotmail , and you t hen saved the draft.. It didnt actually save. ( since you were logged out )
so when you signed in again the last version of the draft y ou are seeing is an older version, as depending on your autosave settings it may only save the draft every five minutes, or 3 minutes, depending on the setting you have set.
Long story short. Since this all happened on the outlook.com server. Theres nothing we can do to restore the draft ( that never actually saved because you were logged out when it tried to save )
We can try to repair your browser to prevent this from happening again.
To help you repair the browser, I would need to know specifically what browser you used.. What did the icon look like.. Was it the new windows 10 microsoft edge browser, was it google chrome, or mozilla firefox? Or the old internet explorer with the yellow slash across the lower case e ?