I Am Out Of Ranexa As Of Yesterday. It Is

I am out of Ranexa as of yesterday. It is too expensive and I have taken doctor's samples Plus paid for many.
I am worried and need to know how long I can do without it without causing health issues? I take 1000 MG twice a day. Had heart attack three years ago and have had two stints two years ago.
Please advise. I understand there is no less expensive comparative. Please advise.