If baby is breastfeeding continuously, and is still unsettled, maybe there is something else going on. Has your nurse/dr checked for tongue tie? Do you think he might have reflux?
It is normal for babies to feed 8 to 12 times in a 24 hour period, but they usually take breaks.
Having a toddler and newborn to look after is tough, triply so when the toodler is sick and the newborn is high needs. Who can you call on for support? Can you lay or sit down with both kids and watch tv or a video while you feed? Can your mum take the baby for a drive or a walk in a carrier so you can take a sleep?
Keep asking for help until you get it,