6 month old not drinking well

My son had croup last week and since then has a nasty cough and lots of congestion. He is also teething and all of these combined has caused a severe decrease in drinking. He used to drink 5oz every hours and eat purées 2 times a day. Now he drinks 1-3 oz every 2-3 hours... and eats half of what he was eating when we do purees...

He has maybe 4 wet diapers a day... sometimes he goes hours without anything. I took him in on Friday and she asked about his diapers and I told her about 4 a day and she didn’t seem alarmed- but I am... im very worried about him not eating well... and I feel like my body senses it bc my supply has decreased also...

Thoughts??