OP if you're as defensive as you are here then I understand why they might seem concerned about you. Please don't avoid them.
Having a baby can be very isolating. When we had DD I went from working full time in a senior stressful role to SAHM overnight. It was very hard to adjust to. Our families were hundreds of miles away and DD was a screaming colicky non sleeping nightmare with major feeding problems and I had PND and PTSD from a traumatic birth.
Once DH went back to work my mum came to stay for a week and took me to the GP. When she went home a week later my sister visited and forced me out of the house for the first time since seeing the GP.
After that, when DD was 4 weeks old, I spent my days in the flat, counting the seconds until DH came home and I could hand the baby to him. My god it was hard and I was desperately lonely. None of my friends had kids yet. The ADs hadn't started working, I wasn't getting any sleep and still battling with DD's weight gain.
Thankfully, my midwives were amazing and recognised I needed daily visits. I stayed on their books for 8 weeks and then I got regular visits from the HV, because it was clear to them all that I wasn't coping and my support network was non existent.
Please don't push them away, those early visits and intervention saved me really. I had lots of horrid thoughts and very nearly walked out more than once. If I'd had my mum close or my sister they would have been the ones looking out for me. In the absence of that, the midwives and HVs did it.
After DD was about 8 weeks I started going to a breastfeeding group and bumped into some ladies from my antenatal class. They are adopted me into their group and I finally found my much needed support network. We went to baby groups together or coffee at each other's houses every day, and life got a bit easier and eventually I enjoyed stuff again.
This is why they're worried about your lack of support network. It's important.