What is the malpractice statute of limitations?

I have read 3 years and I have also read up to 5 years. Which is correct? I have a possible malpractice case of breast cancer and additional metastasis to sternum. I presented to OBGYN with family history of breast cancer (mother and grandmother) and a lump in right breast. He told me it was probably just trapped breast milk (even though I had my daughter a year prior and did not breast feed he said it was probably still just that). I told him the area was tender and he dismissed it all and said "breast cancer doesn't hurt so it’s not cancer". He did not order a mammogram because I was younger than 40 (I was 35 at the time). I had known the doctor for years as he delivered both of my children and he worked in my building in the suite next door so I trusted his medical advice that it was nothing and did not seek out a second opinion. A year went by and I was at my family doctor for an unrelated issue. I casually mentioned it to her. She immediately ordered testing and it turned out to be cancer that had already grown fairly large and spread into 11 lymph nodes. After a ton of chemo and radiation the cancer came back in my sternum and I went thru more treatment. I sought out legal advice and the attorney requested my medical records from the doctor. I have no doubt in my mind the doctor added "told patient to return in a month for a recheck" to my medical record for that visit to cover himself when he realized it was an attorney requesting the records. So now it looks like I am the one that failed to follow up. I am the one that was concerned in the first place and sought out medical advice so trust me if he said come back in a month I would have come back in a month. Is my case a lost cause because of this?