Pumping at work

I went back to work the middle of December when our LO was 7 weeks old. I told them I was nursing and would need to pump twice during my shift (I normally work 10 hour shifts but lately have been 12 hours shifts). I also had a co-worker that was also pumping but her LO was older and she produced a lot more so she only pumped once. They didn’t seem like they understand why she only needed to go once and I had to go twice but tolerated it. I have a job that has to be covered when I am not in there so trying to get someone to do that wasn’t always easy but they did it. I have have felt shamed for pumping and have heard from co-workers that it’s not fair that I get “extra” breaks. I did recently try and cut back to pumping once per shift but my supply dropped dramatically so now I am back to pumping twice a shift.

Well 2 days ago I had a supervisor call in me into their office and tell me I have post partum depression (which I do not have) and that I need to let things go so I should quit nursing/pumping and switch to formula. I am just wondering if anyone else has gone through something similar? Should I just ignore what my supervisor said or should I take it higher? I am really frustrated that they are not being more supportive when I have been an employee there for 7 years.