Should managers relieve you when you're pregnant so you can have extra breaks?

I think my manager is being unreasonable and unfair. There's a nurse at work who's going on maternity leave soon and my manager (also a nurse) is always covering her additional breaks. I'm six weeks and I told my manager I needed to have extra breaks and she told me "If you need extra breaks, you need to go through HR and have accommodations made." I explained that I'm pregnant and she said "Congratulations but you still need to go through the process of applying for special accommodations. I can't just give you extra breaks."

I told her I don't want to do that because I don't want people to know about my pregnancy just yet. She said "Then there's nothing I can do. If you want accommodations, you need to go through the process."

I don't know what to do next. I don't want HR knowing I'm pregnant but I really need extra breaks! Will a doctor's note work if it's just between my manager and me?

ETA that it's unfair because both my coworker and I are pregnant. She's a nurse and I'm not, so I think because she and my manager are both nurses they have a little buddy system going on. I'm getting unfair treatment because I'm not a nurse and I'm not as far along as my other coworker. It shouldn't matter. Everyone should be treated equally in my humble opinion!

ETA 2 I don't know why everyone is downvoting this. Seriously. I asked a question. Don't like it, move on!