When should a chest infection improve?

[Namesnamenames]

DS (3.10) was diagnosed with a chest infection on Monday. He's been taking amoxicillin 3x a day since Monday evening, but there's no improvement.

Temperature still high (39.1 - I've been alternating ibuprofen and calpol since Monday), and he's been asleep for over 2 hours already since he fell asleep late morning (he hasn't napped in the day for nearly 2 years). He's completely off food, not drinking a lot and just generally irritable. I'm waiting for a call back from the GP, but am I being too hasty? I was expecting an improvement by now, but he's worse if anything.

Thanks

My son used to suffer so much with this should be seeing a improvement by now I would take to walk in centre or hospital as may need a nebuliser or steroids to shift it hope feeling better soon

Within 3 doses of the AB is average. (From my experience in childcare) So I would go back.