They get sick all the time in childcare. Especially the first year. So that sounds completely normal.
However, if you're not happy with the care at the childcare, definitely search around or do tours of other centres. Maybe there is one that better suits your needs. We tried one that felt really impersonal and ds hated it. He has been in two other centres, both of which he loved.
I returned to work at about the 6 month mark too and tbh it took me about 6 months to really start feeling like I was back in the swing of things. And try not to compare your LO to other babies. My ds didn't eat more than 1-2 teaspoons worth of food until after 1, and was on the late side to crawl and walk (11 & 16 months).