Red nipples, shooting pain, no let down

I was wondering if you could clarify something to me. I have been feeling some shooting pains and sometimes I don't get a let down or I get a very weak one so Caio cries and gives up after a while. I feel like he sleeps on the breast hoping it will come eventually, he gets fussier if I try to get him off and shows signs of hunger, sometimes let down comes but he drinks for a minute and it stops. Also I notice same thing happens with the pump now, my let down used to come within seconds of start but I have had 10 min sections without any or one comes that last me 1 min only even though in both scenarios I feel like I have milk.

Another thing is my nipples are super red and sore so I feel like feeding hurts even tho the latch looks perfect.

I looked up these symptoms and it seems that it could be mastitis or thrush.

My question is what should I do if I have those and how can I know for sure?

Obgy and pediatrician recommended a lactation consultant

Have a nice Sunday