"Rescheduled appointments"

My appointments are rescheduled regularly. My appt at 9am this morning, was cancelled at 4.02pm yesterday! 17 hours notice. My previous appt was also cancelled. I needed a blood test before my GP would provide my meds, which run out in 2 days. Yet another date of 17th Dec has been made, I have another appt on that date, so now looks like it will be the New Year. I am the carer for my 88 year old mum with various health issues, and my partially sighted son, who also has regular hospital appointments. I have to work around them, and these broken appointments of mine cause problems. I can no longer have an appointment that I know will happen.