Do I have a age discrimination case

I deliver heating oil on Long Island NY for a huge corp. It is a very physically demanding job. Last week they demanded we work 12 hour days for the entire week. I worked 10, but did all of the deliveries they gave me, 36 .I was told I should have called for more work. I said I am 65 years old and I was physically exhausted. My supervisor said I should sit down and think if I can no longer do my job . I have witnesses. I was brought into the office another time and asked if my head was still in " THE GAME" because I handed in a loading receipt that was not signed .There are other incidents over the last four years. I have worked for this company for 20 years and was considered a valued employee. I am at top salary , 5 weeks vacation while new employees make $10 less and will never get 5 weeks vacation. There are other older employees in the same situation as me. Thank You.