I agree on that one. If you have been in hospital with a severe infection and you have had antibiotics, then your resistance to other infections will be severely lowered. On hospital wards, unfortunately, C.Diff and MRSA are rife and C.Diff can spread like wildfire.
I would also suggest that you ask your doc to get a stool sample tested for you.
Also, taking strong antibiotics strips your natural gut flora and can give you bad diarrhea for quite sometime afterwards. Also, it can leave you prone to yeast infections, so I would also advise you to get some live yogurt and start taking some Probiotic supplements to help rebalance these. Hopefully, if you start these right away your stomach may start to settle down as your good bacteria increases.