So, ya. I definitely see the anxiety coming out in your post. First of all, eggs can cause issues but really in the real world? Don't. I doubt eggs had anything to do with your situation. I have had food poisoning and yea, it's terrible. But you saw a doctor who said no. Yes, you had something but unlikely food poisoning. Could have simple gastroenteritis. Blood in stool looks like coffee grounds. Dark stool means you may have been constipated and it came from 'higher up' in your gi tract and this could account for nausea and discomfort as well. And perhaps the stool was older due to constipation and causes a bit of micro tearing on the way out. All of that is reasonable to think.
You would have heard if you gave food poisoning to anyone by now. So, your imagination is now running away from you which is what anxiety does. Anxiety also impacts the gi tract. What do you do to treat your anxiety?