So sorry to hear about your mum.
I had counselling from Cruse when my mum died 11 years ago, they were lovely and it really helped. As hmmSleep said, I found it useful just to have someone outside the family to talk to and unburden myself without feeling like I was burdening them/making them upset too. It did take a few months to finally get to see a counsellor though as they were very busy.
I then trained as a Cruse counsellor a few years ago (I don't do it anymore, since kids got in the way!). It is a very warm and friendly organisation, and the training was very in-depth and professional. All counsellors are volunteers, the ones I trained with all seemed to be either people who had experienced bereavement and wanted to use their experience to help others, or people training to be therapists/counsellors who wanted to get some more experience.
At the branch I worked at we used to go to people's homes to do one to one counselling, but some branches do have an office with a counselling room where people can go instead.
I'm sure they won't mind you calling to follow up on your email. There is also lots of information on their website that might be helpful in the meantime here
Well done for taking the first steps and going to your GP, hope you get some help soon xx