Do I have grounds for a discrimination lawsuit

18 months ago my doctor gave me a 20 pound weight limit an my employer changed my job position. When I said the overhead doors where more than 20 pounds he told me I didn’t have a choice an quit being a crybaby. I felt my job was at risk so I made do the best I could. Another 9 months I could no longer work the long hours they wanted me to work. My doctor filled out ada paperwork stating I could work 8 a day 5 days a week. When I came back they told me they would accommodate me if I would take a schedule that others had turned down. Again felt my job was on the line. Not I’m excluded from meetings an safety meetings. I am not given any info on changes. Instead of getting help with the job like others do while performing the job I have limited an sometimes no help