Baby development update

Yesterday I was on the bus with the baby in the Baby Bjorn, and Asher was crying inconsolably. I was standing up, humming to him and jiggling, despite being physically and emotionally exhausted, and he would settle for a few moments then start up again. The poor little guy was so tired and there was nothing else I could do to help him sleep when a very young man suggested that I turn the baby around to face inwards to stop his crying. I thanked him for his suggestion and muttered something about not being able to do that on the bus, knowing Asher's feelings about facing inwards when I'm wearing him. I realised then that the little guy has been crying and unsettled a lot for the last week and a bit. Last Tuesday his unsettledness was a one off, but he hasn't had a good day since then (except perhaps Monday).

So despite all this grizzling and unhappiness his development is coming along in leaps and bounds. His night-time sleep is really good. He generally only wakes up about once per night and he slept through the night for the first time ever on Monday night (from around 7:30 or 8pm to 6:30 or 7am). The other big change is that he can reliably roll from his back to his front, and he's doing it all the time. He's rolled from front to back quite a lot, but it always seemed kind of accidental, now we have to be super careful about leaving him anywhere because he can and will roll off. We tend to put him to bed down one end of his cot and wake up to him still asleep, often on his tummy and usually with his feet right down the other end of the cot.

I'm finding Asher's fussiness really difficult and it is making me doubt what I'm doing with him - is he hungry? Perhaps I should be supplementing with formula or starting to feed him solids? Is there any way I can help him sleep more during the day? I can't tell whether the grizzling is making me stressed and flat or whether I would be having a hard time anyhow? Is the baby picking up my unhappiness and upset because of it? At 18 weeks perhaps he's teething?