3 month old clingy oh so clingy

My 3 month old is going through a rough few days. About four days ago she started becoming really agitated. The doctor checked her over and told me it was probably a bad stomach so she gave me what they call here in Italy fermenti lattici which is basically a probiotic which helps breaks down stuff in the gut.

She's been taking it for 5 days and I don't think it's helping. My poor baby is in pain. I can see it. She's not a cry baby and in the last five days she has been non stop.

She also won't let me put her down. She cries immediately . Intensely . She usually loves the sling but she cries for a good 5 minutes before eventually crashing out due to exhaustion from crying .

She won't take a dummy, hasn't since birth. She's crying over silly things . It's not like her. She's such a happy baby

Something's definitely up and I just want to help her ! Any ideas! ?

Thank you ladies