Debating whether of not to call the doctors about my mental health

I’m struggling real bad with ppd. idk what a doctor would even do to help me, so I’m not sure if there’s not much point. I have so much going on and I’m so incredibly lonely. My mum is the one person I usually rely on and talk to. but she’s got cancer and was going through really brutal chemo but they have stopped it as her cancer has spread to her other organs. I think I’m gonna loose her. I just need her to think I’m okay I always do the best I can for my little 4 month old boy, and more, but I feel so low and it’s exhausting putting on a fake smile for him all day everyday. I feel guilty that we don’t go out.