I need to ask a question about my Kitten Pumpkin

Crystal

I took in this kitten like a month and half ago, she was a stray. When I took her to the vet a day after taking her in they told me she had a high infection, mostly likely in her respiratory. They gave me antibiotics to give to her and she became better she became very active and she eats a lot and they told me she was well enough to be around my other cat but they never told me if she was better as in the infection is gone. That concerns me because I want to believe she’s better but I get so freaked out as well especially with the fact that she breathes pretty fast and when she breathes like that it makes me believe it’s still there. Is fast breathing normal for a 14 week old kitten? Should I get her blood retested to be 100% sure?