"Follow up outpatients"

I had a heart attack on 6th May this year, and was rushed in to Kettering's new cardiac unit who cleared and fitted a stent into the heart artery. I have no complaints about my treatment it was 1st class. However I was assured by my GP that an outpatient appointment with cardiologist was required for 14wks after the op, that time scale took it to 12th Aug this year, and I have been told by appointments that they have not received any requests, and the secretary tells me that there are no slots available for August and September. So what am I to do, I'm having no follow up to ensure things are working properly. I am retaining fluid and need diuretics, my GP won't prescribe anything until I have had the outpatient appointment. So I'm just left dangling in the middle. Not very happy.