Help? Did anyone else’s milk supply dip?? Or stop?

My son is 5 months. The last two weeks or so I’ve noticed he struggles to eat. Either my let down isn’t fast enough or he just isn’t getting milk. I’ve tried hand expressing to show him milk is there but I sometimes struggle myself to get any. Just now he was screaming bloody murder! He latched & unlatched repeatedly because he wasn’t getting any milk. I tried hand expressing & didn’t get any milk. I had my husband give him a bottle from stored milk I have. He had 2oz. I pumped for 10 minutes & got less than a quarter ounce! I use to be able to easily pump 4-6 ounces in that time frame. He has never had a whole lot of wet diapers, 5/6 a day & I want to say in the last month it has been 4/5 with 2/3 poops. I have a doctors appointment tomorrow morning for other concerns I have & I already called a lactation consultant to meet with her but I’m waiting to hear back. Any advice or help is appreciated. I feel defeated & really don’t want to stop breastfeeding.