Frustration

When one is frustrated and need an outlet, but cant find any outlet,...
Is it better to turn frustration into anger or settle into depression???

Past:
I've always been a pessimistic person, not pessimistic to the point of wanting to end my life (I love myself too much to do that and still quite sane), but dully pessimistic nonetheless. The kind of pessimism that accompanies depression, constantly finding myself in a low-energy state, lacking interest in anything and would just be happy if everybody leaves me alone. Life was lived one day at a time, yesterday means nothing more than tomorrow. No energy, no soul, no dreams cos nothing matters....

Present:
A deviation from the past, my frustration has been channelled into a thick pool of anger. For someone who had been described as having 'zen-like qualities' I think many would be shocked to find me as I am now, stunning unknowing victims with uncontrolled lightning discharges, friends and foes alike. I've never let myself be so angry for so long before. I'm undecided if I should allow myself to continue in this state, or find a new one. For one, I'm reluctant to give up this state so easily now because I am feeling alive again. I am affected by emotions that has not been felt in ages. I no longer find it difficult to wake up early for work nor feel the lethargy that hangs over my every movement. My bubbling angry energy needs an outlet which I have been pouring into my work and yielding impressive results. Not surprisingly, my relationships did suffer a setback. Nobody likes their head to be snapped off on a Monday morning, more than hearing somebody moan about how bad their day had been. This is not an ideal state to keep up for the long run, as what is life without friends, without people who care to share my highs and lows, my success and my failures?

Need:
A better way of venting my frustration.

Regret:
In the course of finding myself, my supporting, loving bf has been on the receiving end of many of my outbursts, something I'm not proud of. I hope our relationship is strong enough to withstand the test of time, distance and emotional turmoils. Love you darling.