Baby boy suddenly very lethargic and weak

[SL8]

I posted here a few days ago about my baby squirrel Martin, he was doing very well since then, he really perked up and enjoyed running around and climbing on me, and cuddling under my shirt. It seemed like he was just getting stronger and stronger every day, until now. I woke up, and he was just laying there on his side in his cage. Very lethargic and weak, can't really stand all that well and won't feed. What happened? I'm very worried about him, and considering taking him to a wildlife center or rehabber in my area. I only want the best for him, and if surrendering him to someone more qualified is what he needs, than that's what I'll do.

[HRT4SQRLS]

How old is the baby? Put the baby up to your ear. Do you hear clicking with every breath? Listen carefully.

[HRT4SQRLS]

I went to your other thread. A few days ago it was determined he was about 6 weeks ago.
You really need to get this baby on formula. I wouldn’t give Apple or baby food. The baby needs calcium to grow bones.

Let’s rule out aspiration pneumonia first. Then we will look at the diet.

[Rock Monkey]

When you hold his mouth close do your ear do you hear clicking?

If so, that suggests inhalation pneumonia which is very quick to progress.

Keep him upright and tucked in between layers of your clothing.

[FergieBoo]

So sorry, hope you can figure out how to help him... I saw you said he had started eating apples, could he have gotten any of the seeds? They can be toxic...