27 weeks pregnant and not sure if this is normal or no

27 weeks pregnant and For 3 days already, I have a weird pain when I touch with my finger my left abdomen, only when i touch either my fingers, i didnt fell, I dont have any bruise I have no idea what could this be, I found this when my 2 year old try to touch my belly to say hi to her little brother and I had to take her hand away l because it was very painful, but again only to the touch of my finger, on top of that I'm with diahrrea since yesterday 😭