Charge nurse asked me to use wearable pumps

I'm a procedure nurse and work 10hr shifts. I'm 9mo pp, I pump before work, 20min at 11am and 3pm. But the last few weeks at work have been busy and my charge nurse has been making comments about how I should use my wearable pumps so I can pump and still give patient care. And I really wish it were that easy, but I have noticed I usually only get out 3-4oz wearing my wearable cups for 30mintes compared to the 5-7oz I get out in 20minutes when I can sit and use my spectra. I feel so much pressure to support my unit but I am also really uncomfortable when I can't pump efficiently and I'm worried over time this will hurt my supply. (Right now when I get home I pump and can usually make up for the day). The other day the charge nurse asked me how much longer I expected to be pumping, pointing out I have been back from maternity leave now for 6 months, was I "really going to still be pumping". Also my coworkers have asked me to stop telling them I'm going to pump cause it sounds gross, they asked me to call it "meal prep". What do I do? Do I go to HR? I tried to talk to my manager but she told me "try and work it out".

Update: I confronted the charge nurses privately and one on one as my manager suggested. They seemed indifferent. Next thing I know I am in my mangers office being told I am overly emotional and they are "concerned for my wellbeing". They list out that I am overly tired and seem very anxious about my daily schedule and that I would rather be on break then help the team out. I cried they left and my manager gave me an Employee Assistance Program brochure. So now I'm writing an email to HR documenting all the comments I have heard over the last couple months to put in my personal file. I really do like my job so I want to find a way to work it out with these charge nurses.

Also for context I do live in the USA and I have been a nurse for 14 years.