Massachusetts employment on FMLA and ADA. Do I have any legal action?

Hi - I live and work in Massachusetts. I’m on FMLA and my Doc also filled out ADA paperwork for my employer. My employer has over 50k employees globally. I have worked for this company for three years. Halfway into my second year I had a Crohn’s flare. Went on FMLA : one for five weeks and a few months later after another flare, took another 7 weeks of FMLA. This past February (2019) my doctor filled out all the necessary ADA & FMLA forms to my employer and I recieved conformation it was all approved. On 1/25/19 I had emergency surgery for a complication of Crohn’s I was out 10 days in the hospital. I had to have a second surgery a week after that. I was out for 3 days for that one. This week, 3/4/19 I received a written warning for poor performance, inconsistent performance. I was also working this year when I was sick I would come into office and work because that what the culture is here. Do I have any legal action? I feel like I’m being forced to resign/leave. I really can’t afford a lawyer in Boston. And the stress this has caused me has been hard on my body/immune system. Yes- I’m already looking for a new job.