How do I keep track of cases when my workload suddenly spikes?

On a normal day you manage your cases well. When the volume spikes, things slip, and someone who was counting on you gets missed. That is not a sign you are bad at your job. It is a sign your system works for a normal load but not for a flood. Willpower will not fix this, because the problem is not effort. When there are too many people to hold in your head, your head is the wrong place to hold them. What you need is something outside yourself that catches every open item so nothing depends on you remembering. Build one simple list of who is waiting and what they are waiting for, and check it first thing each day. When a spike hits, that list becomes the thing you trust instead of your memory. Start it today, even rough. It is far easier to keep a list running than to rebuild who you dropped.