I identify so much with that because this waiting that I've had for the surgery on my ovaries and the lack of control I had over all that and the seeming "dont care" by the medical profession made me feel despair, hopelessness, increased pain and depression. Complaining about it was difficult also because the complaint took so long for them to deal with (a couple of months) and then they made me jump through several hoops before they'd reschedule the operation. It's been three years since they first noticed these lumps, 2 yrs of them "watching" them to see what would happen, and a whole year now since they first tried surgery. I guess I do think that if I hadn't have complained to the trust they wouldn't even have agreed to do the surgery yet even...and we still don't even know if the masses are cancerous. I think this is really neglectful and if something happens to me because of the amount of time that they have taken, I hope my husband sues them for every penny he can.
My point being.... I think depression is natural and normal considering how long the cardio appointments are taking and the uncertaincy you are dealing with.
I think it reprehensible that our NHS is in this state and doctors can treat us like this.... the anxiety so much waiting causes has horrible negative effects on the patient, the person, the individual and that effects his family and his friends and his daily life.
Consider complaining, as this may help you to feel you are doing something to improve your experience. You need to keep written notes of each appointment, or phone call, or letter, who you speak with and what they say and how you are feeling. I would hope that the complaint hurries along your treatment and improves your care if at all possible, but do be aware the process of the complaint takes awhile also.
There are many other things you can do to help ease the pain of depression but you have to find the things that help you personally. Not everything helps everyone, it's another of those YMMV situations. Some ideas are:
Do something about the situation that is depressing you. Do not try to ignore it or avoid it but work on through it.
Find and utilise what daily activities are soothing for you, whether this is something as simple as a hot sweet cup of tea (dang the sugar) or a hot bath (beware the hypo) or a walk each day (if this is physically possible).
It's very nice to have something to look forward to, whether it be a holiday (even planning an imaginary one) or an outing to the theatre or whatever else you'd like to do that takes a good bit of effort and planning. The act of accepting that challenge and giving yourself an intrinsic reward is really emotionally positive.
Talk to others about your feelings, chat on here, speak to someone you trust, ask for therapy from the GP even, anything that keeps you talking can help.
Find some way of helping others. Depression (and I have experienced it many times myself so I feel I can say this without it sounding accusatory) depression is 'selfish'... if you can consider others rather than yourself that can help ease the depression also. Whether you manage to somehow help a loved one or even a stranger, it is really personally rewarding and can help lift that depressive feeling.
Don't feel ashamed if you do need some antidepressants, there are many more modern forms of antidepressants these days, I doubt very much whether you'd be offered valium even if you did ask for some medicinal help.
Think of having a list of things that you can do in and of that instant if everything gets too much that you can't think straight and are emotionally overwhelmed, whether it's to call a trusted friend or the samaritans or to go see your GP or even something as simple as to post on here.... I know everyone here would be more than willing to help.
Don't give in. We're on your side and you're not alone.