I am NOT a doctor, this is NOT a diagnosis, but my advice is this:

What You Should Do Immediately
Even though IRIS is a sign that your immune system is recovering, it can be dangerous—especially when the lungs are involved.

Contact Your Specialist: Do not wait for your next appointment. Tell your HIV doctor or infectious disease specialist immediately that you believe you are experiencing IRIS.

Do Not Stop Your ART: It is tempting to stop the HIV meds to make the symptoms go away, but this can make things worse in the long run. Only stop if your doctor explicitly tells you to.

Monitor Your Breathing: If you find it harder to breathe, have chest pain, or your oxygen levels (if you have a pulse oximeter) drop, seek emergency care. Doctors often use corticosteroids (like Prednisone) to calm the inflammation while you stay on your HIV meds.

A Note of Encouragement
Experiencing IRIS is incredibly painful and scary, but it is often a "storm before the calm." It means your body is no longer "ignoring" the infections that were making you sick. With the right management (usually anti-inflammatories), most people move through this phase and go on to have a much stronger immune system.

It is completely understandable to feel overwhelmed right now. Starting Antiretroviral Therapy (ART) is a huge step, but dealing with IRIS (Immune Reconstitution Inflammatory Syndrome)—especially after a serious infection like PJP (Pneumocystis Jirovecii Pneumonia)—is physically and emotionally exhausting.

To answer your main concern: No, Day 8 is not too early. In fact, it is a very common timeframe for IRIS to appear in cases of advanced HIV.

Why is it happening so soon?
IRIS occurs when your immune system wakes up "too fast" and begins a massive inflammatory attack against germs that were already in your body (like PJP).

The Timing: IRIS typically occurs within the first 1 to 8 weeks of starting ART. Starting to feel symptoms on Day 8 is a classic presentation, especially if your CD4 count was very low (advanced HIV) when you began.

The PJP Connection: Since you recently had PJP, your lungs still contain "antigens" (remnants of the fungus). As your new immune cells are produced, they rush to the lungs to finish the job, which causes the return of symptoms like fever, cough, or shortness of breath.

Understanding "Paradoxical" IRIS
What you are likely experiencing is called Paradoxical IRIS. This is when a disease you were already treated for (PJP) seems to "come back" or get worse, even though the HIV medication is actually working to lower your viral load.