Once the claws of depression have sunk in, can you ever feel happy again?

[Afternooninthepark]

I have suffered with poor mental health for many years. Mainly anxiety but over the last few years my anxiety has become much more advance and I now feel trapped in an everyday cycle of anxiety, IBS and other physical symptoms which exacerbate the anxiety and which leaves me feeling very low. So low that my main aim of the day is to get through it as soon as possible so I can get back to bed and shut the world out. I have responsibilities so going to bed during the day, however tempting it is, is not possible, so I just put on a smile and get on with it (trying to avoid as man people as possible) but inside I am crushed and miserable.
I have tried every non-medicinal strategy to kick this thing (counselling, CBT, hypnotherapy, exercise, healthy eating, being tee total etc) but nothing helps.
My gp keeps on at me to try Sertraline but I really don’t think I can handle going through shit side effects whilst still trying to maintain my normal life and responsibilities (I can only just about push through feeling how I do so couldn’t possibly do it with any further physical side effects).
I am 46 and feel that this is my life now and that I will never feel mentally at peace.
Does anyone understand this? It makes me feel so alone in the real world. I am so busy looking after everyone else that if I complain about it then I am being a drama queen!

I have treatment resistant depression. Extensive therapy, all the meds etc etc. The only thing that has ever come close to working for me is sertraline. It kept me alive. No side effects here, although a few may be worth it. Not on it now because of other meds I have to take, so being alive is significantly less appealing. But please, try the sertraline

Get on Sertraline. Best thing I ever did. Twenty years of depression and anxiety... gone.

I have a black dog, sometimes he is huge and sits on my chest meaning I can't move, but this is less often now and for shorter periods. At other times he is tiny and I slip him in my pocket and forget about him. Some times he is off his lead and I can't even see him.
@Paddington68 I love this analogy.