Strange Feelings - Bereavement?

Hi guys. I've recently been having extreme intense feelings that I can't face the future and when I think about it I either have a panic attack or very nearly. It is very strange and very horrible. It is like I want to die or can't go on but I am not suicidal in the sense that I truly want to die because I don't believe that I do really, I just want to get back to normal.

I believe this is possibly down to a bereavement, I had lost a friend 11 months ago - but everything else in my life at present is ok, (positive even). It was a friend who was the same age as me that I lost, we share the same birthdate. We were expecting it as she was ill, so it wasn't sudden in a sense, but I did not know "how long we had left" with her so it was still a shock.
I've managed these 11 months somehow and I have been going to work and doing everything as normal but over the 11 months I have had some feelings on and off, like deep waves of depression sweeping over me, staying different lengths of times. I have had also some anxiety feelings, which have not all been the same - some are intense dread and others are just panicky feelings that I can more easily deal with.
I am frightened of these feelings that I can't face the future because up until a week ago it was not like this - it was not a problem, I thought about the future "normally" like anyone would, not with feelings that I can't face it. I have been that anxious and depressed that I can hardly eat, and this morning I had diohrrea (i had this problem a couple of times over the last 11 months too). I have a small appetite anyway.

Does anyone know how I can deal with this and has anyone else had something similar? Can anyone offer any advice or hope of light at the end of the long dark tunnel? (i need advice on managing these intense feelings of wanting to die / can't face future, advice on managing the intense anxiety - at the moment I can go out etc but I have been off work all week and not sure I can go back yet..., and advice on bereavement, I know about panic attacks and how to control them but I still keep getting them - I had one last night).
I want these feelings to go away, but I am afraid what if they don't? If they don't go away, can anyone tell me that it is possible to live a fairly normal life despite these awful feelings?
I have some good friends and supportive family around me and apart from the depression I am otherwise fairly happy so it is a strange mix of feelings!!
Does anyone agree that this is probably part of my bereavement?