Baby lost some weight

Hey there! FTM here freaking out.

My baby boy is 4 and a half months EBF and up untill now he always gained weight at a healthy pace (started gaining a little bit slower once he hit 4 months).

We are going through the sleep regression, though it seems is a lot better now, he is more active and completely distracted by everything 🤣.

Yesterday i weighed him and it seemed that he lost approximately 100 grams. Nothing in his routine changed, he eats the same as ever, he has plenty of wer diapers and does not seem fussier than usual. That is why it came like a shock.

Last time the doctor weighed him a little over a month ago he was at 5.05 grams and now he has 5.500 grams (he was born at 35 weeks). We have an appointment tomorrow, but i am too worried and i feel like i m failing him...i mean i m the one feeding him...

Can someone share their experience, please? Sorry for this long post.