You could try with autosuggestion. Relax before sleeping or meditate with something like:
I`m calm,peacefull, confident. My mind is filled with happy and positive thoughts that neutralize any negative thought. I love bridges, they help me to get on the other side. They are man made and safe.
Imagine crossing the bridge happy,walking over it ,looking at it
or go face with the bridge, kick it yell at it,tell to it "I`M NOT AFFRAID OF YOU;YOU PIECE A ... STONE"
But it would be better to carry good thoughts.
Ok, i guess you get the point
Also if you lack of Mg your nerves get thinner and you start to lose your head, stress gets you easier for things that you wouldn`t normally care for.Eat bananas,soi,peanuts,green vegetable,potato not pealed.
For depression is good sun. Sun stops creating some depressive hormon.