Anger: depression or anxiety?

A little bit of background: I've suffered with depression and anxiety for as long as I can remember, which I strongly suspect is due in part to growing up with Tourette's and OCD and the lack of information or understanding around the subject throughout my entire childhood. Eventually I discovered answers for myself in my mid-twenties, and have been managing it since then (I'm now 40).

For the most part, I am good. I have really bad days still, but never anywhere near the lowest points I've been. I've had help the last couple of years with the aid of Sertraline, which aside from its side effects has been an absolute miracle drug for me - mostly combatting my anxiety and depression, and for the first time in my life completely knocking out my Tourette's (for a while I even forgot I had it).

The one thing that I can't seem to deal with, though, is my anger. I'm not anywhere near as explosive as I used to be, and I have developed the ability to catch myself before I get anywhere near the point I used to (I haven't smashed anything for quite some time now).

But I can't shake it. I still find myself getting incredibly angry over what should normally be something trivial. My laptop has had issues for 3 days running and I've had hold the power button and do a disk check, and today it nearly drove me over the edge and I found myself slamming my closed fist on my desk enough to make everything on it jump an inch in the air. It takes less than 5 minutes to do a disk check and reboot, and there weren't even any disk errors today.

I recently came off of my medication as it's been over two years and I need a break from the side effects. I mention this because the anger is still there whether I'm on the medication or not, but its definitely still there. It's actually in my family - a trait my father and my brothers all possess. The medication is a problem sometimes because rather than allowing me to deal with it head on, it eventually makes me not care enough to do anything about it. I do intend to start taking it again, especially after this evening.

I'm a rational, intelligent human being. I can't tell if the anger is because I'm depressed or anxious, and I don't know which end to tackle it from. When I get like this, I used to explode but now I just lay down and go to sleep until it subsides. Not being able to tackle it makes me feel useless, which makes me feel I'm not equipped to tackle it, which feels terminal, which then makes me more depressed, ad infinitum.

I'd really like to hear from anyone who has been in a similar situation, perhaps you've found coping mechanisms, or perhaps you've at least worked out whether it's depression or anxiety. Anything at this point that might give me some hope that I can deal with it.

Thanks x