My poor 2 week old baby screams in pain every evening - and until about 2am. Her face goes bright red and she goes stiff as a board....

She doesn't burp after her bottles (of formula). We sit her up and slap her back repeatedly but burps very rarely come out. I think the little bubbles are getting into her intestines, where they need to come out as wind. We have tried infacol gas drops but they don't seem to be working. We swaddle, we have tried warm baths, tummy massage....

What can I do to offer her relief?? The lack of sleep is one thing - but I can't bear to see her in pain.