Is this normal?

So my son is 7 weeks and 4 days old and for the past few weeks he’s been put on to lactose free milk as his doctor seems to think he’s lactose in tolerant. Ever since he’s been on the new milk his poo’s have been extremely firm very big and what I’d class as an unusual colour. I’ve tried getting him into seeing the GP but because of the whole corona virus thing happening I’m not able to get him seen😩 he’s in so much pain trying to open his bowels to the point where I have to assist him in trying to get his poo’s out😣 Do these look normal for a 7 week old to be passing or should I seek help?