J,
Hi and welcome to beyond blue.
To answer the obvious question, I don't think you are going insane.
Now I am not a professional counsellor and the only things I know are based on my experience with my psychologist etc. But when you said that you experience anger attacks and being annoyed at yourself and other people it sounded a little like me (the last part). I am getting better at dealing with it. In my case, I have extremely high expectations of myself and others (in work) that if these expectations are not then .... Or I'd feel under immense pressure to get something done and feeling like a hair trigger where anything would set me off. I would not verbalize it but let the anger build internally. My psychologist then told me about the 4 zones, blue, green, yellow, red. And with depression or anxiety I would go from normal or empty to REALLY frustrated at the flick of a switch. Again, for me, this was all related the pressures I felt from work. So I got help ... to help me cope better with what was happening to me.
A quick note on faking it, or hiding your problems. With all things there are many ways to resolve a problem. You can either try to do it yourself. And you have come here, which is a good start. But if they does not work, there is no shame in getting professional help. Being able to talk to someone in real life about your problems can be really helpful. Sometimes you need a support group. Contact and connection and being real to yourself.
Hope that helps,
Tim
