Thank you for your response.
Unsurprisingly, I didn’t expect to find a solution to one of my biggest problems in my first few posts on an internet forum. However, I don’t have anyone I feel comfortable discussing this problem with, so, when I take the time to put my thoughts down into words, I feel better posting it online (rather than not at all), as I feel that I’ve at least discussed it with someone, rather than keeping it to myself. There’s always the off-chance that someone will respond with something useful. I don’t expect a quick fix to my problems. Obviously I don’t want to bother people with my issues, but I do find it difficult knowing what to do sometimes. Hence why I’m treating this a little like a support group (or similar), where I just have a chance to vent/get things off my chest.
Update: I had intended to post the above much sooner, but life got in the way and I kept getting distracted etc. Today, however, I went to see my doctor. I have been recommended to have some blood tests and, depending on the results of them, I may be referred to another clinic. I’ll have to wait and see for that.