I need advice! Noah has just done a poo which was dark green (sticky) normal consistency with the…

I need advice! Noah has just done a poo which was dark green (sticky) normal consistency with the mustard colour coming through afterwards. He's been constipated (I think) the last few days. But he has also been drooling/sucking his hands and bobbing his tongue out as if he's rubbing his tongue on his gums... could it be he's just constipated or the start of teething? 🤔 (I can post a picture if anyone wants to see)