Nipple changes after breastfeeding?

Hi All,
Me again with yet another question.
Yes seeing a Dr about this one too.

So I breast fed my daughter till she was 3, she’s 4 in 2 months, and I’ve noticed that now my nipples which were always quite perky now seem to point down – once they feel the cold they are back to perky again, but when relaxed they seem to be sagging.

Never heard of sagging nipples though?!

Has this happened to anyone? I’m assuming it’s from all the sucking – pulling the nipple down etc and they might change once my breasts have time to get muscle again?
Completely made that up but it makes sense as the baby pulls down on the nipple.

I’m worried about breast cancer but both nipples are doing the same thing .. I’ve done a breast self exam and can’t feel anything but that doesn’t mean anything.

I just wondered if other breast feeding mothers experienced something similar?
I have small breasts and my nipples are bigger than before but not by much.

Thanks guys x