I would feel great sadness, loss, emptiness and hopelessness initially. I can't say whether or not I would experience shame.
Long-term I don't know how I would feel or how I might respond. I would hope that despite my error I would've learned the appropriate way to treat people and that I would devote the remainder of my short existence to something meaningful that is beneficial to those in my small circle of influence that are left behind when I am gone.
Even though the "man upstairs" was proven false I would hope that I still live my life exhibiting peace, love and kindness towards others.