propanalol and depression?

I was prescribed Propanalol 3 years ago, during a messy divorce. It helped with physical syptoms (symptoms) (Tachycardia, tremors etc). It started off at 30mg a day. I have been on 120mg now for 2 years or so. I have also been depressed ever since. I do not get seen by my GP, it is simply on repeat.
I have functioned for that time, in a none to happy, yet no physical symptoms state (if I forget my meds, I really suffer, sweating palms, palpitations, the works). So I don't see how I can not take them.
Thing is, recently my very best friend died of cancer at the age of 39 (we have kids the same age). I can see how this could cause depression anyway, but I tend to spend most of my time sitting outside so that I don't do anything 'bad' to myself.
I have been depressed in my teens, yet never felt suicidal. This is really scaring me. Do you think Propanalol may be contributing to this situation? I have never been so worried about my mental health in all my life (I am almost 40).
Should I change/ try to phase out Propanalol?
Please help.

[ILADVOCATE]

I took that and yes it can cause depression as a side effect but as it is a beta blocker which is its primary use as a heart medication any changes in dose or titration must be done under a psychiatrist's strict supervision. As well, there are many other options as regards medications so you could ask them what the available options are and what you believe the side effects you have that are impacting on you and they could tell you what to do from there.