I Have Been Cancer Free For At Least 4 Years,

I have been cancer free for at least 4 years, maybe more. I am never sure how you calculate. I had Stage 3 Triple Negative Breast Cancer in 2009. I completed treatment in 2011. I have been seeing an oncologist regularly since then, but have been assured that I am fine. So we stopped doing scans, etc over a year ago. For that past month or so I am unreasonably tired, dizzy when I stand and ridiculously short of breath after the slightest exercise. I remember those feelings.... For financial reasons I am trying to take this year off from medical bills, plus my insurance changed and I can no loner go to Mayo. Would it be very unwise to wait until next January to see a doctor? Or might these feelings easily be something else?