Decrease in feeding

Werdah

hey guys! just wanted some mommy insight into what I'm going through. my little son is Turing 4 months in a day or two and in the last 2 weeks he's been feeding less frequently and for shorter periods. he used to feed about 15 minutes but now is only feeding 5 to 7 minutes. if I try to get him to drink more he starts crying and pushing my breast away. he is keeping his feeds about 3-4 hours apart. I tried to give him EBM because I thought maybe he wasn't interested in the breast? he used to be able to drink about 150 ml which I think is about 4 to 5 oz but now will only drink 70-100 ml or 2-2 and a half oz. should I be concerned? he is still having about 6-8 wet diapers. I'm just not sure what to do or if I should be worried. I'm a ftm so everything is super new to me. would love some insight and if any of you are going through the same thing what are you doing to tackle the concern?

thank you in advance!