"Unable to ever see my usual GP"

I'm a Crohns patient who has had the same GP for over a decade. For the past year or so it's become practically impossible to get an appointment with them. I realise this probably isn't the practice's fault and part of a bigger issue, but when you have a chronic illness or are elderly, it's important to have a doctor who knows you. We don't like having to keep retelling everything to a new one because ours is never available, especially if that person is constantly changing because we need to be seen as soon as possible. To be honest it discourages us from getting help when a problem may start (and thus be treated more easily). I know it's likely down to the practices being overrun due to constant housing developments that never include additional NHS practices in their plans. Something needs to be done because we're getting left by the wayside.