newborn with stomach bug

I'm a ftm who is breast feeding both nipple and pumping into a bottle. I have a 5 week old who started vomiting Sunday night and about 4 times on Monday. On Tuesday we took him to the doctor ... where he vomited again in the office. The doctor said the baby has a stomach bug most likely which he caught from my husband who was feeling sick on Saturday. The doctor said to give him pedialyte after each time he vomits. He didn't throw up the rest of Tuesday but then yesterday (Wednesday) he threw up in the evening after my husband gave him 3 3/4 oz from the bottle. He then threw up again an hour later after I gave him 15 minutes on the nipple. We put him down to sleep at 11:30pm and he didn't wake up to eat until 4:30am .. I gave him pedialyte again but am so worried that it's not enough to sustain him. I also don't want to overload his stomach right now. Have any of you moms experienced this with your newborns?? I'm so scared and feel like I don't know what to do. I could really use some help/ advice. Thank you