I read every word you wrote Jonny and, as I scrolled down, everything I thought of someone else has suggested. Except one...... Those of you that know me well know that I won't normally talk religion but I won't back away from discussing it either.
Have you considered some form of spiritual help? I'm a Christian, (maybe a little rough at the edges verbally when provoked!) but there are many different faiths around the world that you may find helpful to find if that's whats "missing" from your life.
PM me if you want to discuss it further