Telling your boss?

When is too soon to tell your boss/employer???

I’m 6 weeks & straight up MISERABLE. Nausea & gagging all day long, extreme exhaustion, headaches etc etc. I used a sick day today because I just physically couldn’t do it. I have more sick days but I’m not the type to call out all the time. I also just applied for a remote position and don’t want anything to impact that 😭😭

I haven’t even had my first appointment with my dr yet !!!