For the iron ODS, I wouldn't worry much about it. You probably didn't take enough to do any damage.
I accidentally ODd on vitamin A once. (Yes, it was really accidental). I used to drive over the road for a living and would take vitamin supplements daily. So that I could take them while driving (and not be distracted), I'd put the dosage into empty medicine bottles and take all of them at once. On this particular day, I grabbed the wrong bottle by mistake and by the time I thought to myself, " I don't remember taking so many before... " I had swallowed around 50,000 IUs of vitamin A.
I immediately called the poison control center - which gave me a recorded message to leave my number and they'd call me back - if you can believe such an audacious thing is possible. Two hours later (yeah..." two hours ") I call back and speak with someone who told me not to worry. It's a good thing overdosing isn't a REAL emergency...
Thus, you're probably okay with the iron - just don't make a habit of it.
As for your mental condition to go as far as doing it in the first place, you need to talk to someone. It doesn't have to be a doctor, necessarily. Even talking to a friend helps to relieve pressure. They may not be able to do much in the way of a solution, but just that act of talking things out in the open helps relieve pressures. If you're still feeling "not up to par", then I would suggest professional help.