Hi K.!
It's been a while (my son will be 13 in a couple of weeks), but I recall that he nursed almost exclusively until he was actually about a year old! He was a big, squishy baby, too (although he's very lean and trim now)! He didn't display any interest in trying solid foods until he was about 8 months old, and wasn't really seriously into eating until about 18 months!
The sleeping-all-night thing is another story. I can't remember when Liam started sleeping through the night because we co-slept and he and I both got quite used to him just latching on in the middle of the night when he needed to, and neither of us really awakened.
I will say this, though. Now that you're back to work, he may want to shift his connecting-with-you time to the overnight hours. He may even increase his nighttime feedings just for that purpose. You have to do what works best for *your* family, but I would encourage you to factor in that as long as he's continuing to breastfeed, you may want to figure out how you can best meet his needs for connecting with you *and* your need for getting your extremely important rest. Perhaps you can arrange to have a co-sleeper next to the bed so your sleep doesn't have to be too disrupted?
Remember that any changes he is presented with at this stage in his life is totally new ground. Also, it has been said that for a baby under the age of 1 year, his wants are equivalent to his needs. He has a biological need for his connection with you.
Here's a scientific basis for that, in fact. A few years ago (when I was a LLL), I remember reading about a discovery concerning immunity and how a nursing pair could actually "communicate" (for lack of a better word) through Mom's areola. So, if Baby had picked up, say, a cold virus, he would communicate that through the breastfeeding contact to Mom, whose immune system would whip up an antibody and return it to Baby in the breastmilk. Baby would never exhibit cold symptoms (or would only exhibit mild cold symptoms). Well, *that* blew me away!!
And, my son's very, very, very healthy early childhood, I think, bore that out.
One thing that may also help to reassure him and meet his need for connecting with you (if he starts displaying a need, that is) is increasing your skin-to-skin contact with him when you're home.
I really, really admire your commitment to nursing your wee one even though you've returned to work! Your son is a lucky little guy!!
Marji, missing those squishy little legs and arms!
P.S. I would definitely follow his lead, as you are doing, concerning solids. Some babies put off starting solids in earnest until after 12 months of age, and there's usually a good reason for that. There may be allergies, sensitivities, or intolerances that kids outgrow when they reach that 1-year landmark. I think that may have been the case with my son. I am delighted to report now that he has no food intolerances and never displayed any once he started eating solids. In fact, he would eat almost anything I gave him, probably because he was exposed to it somewhat through my breastmilk.
P.P.S. Sorry this is sooooo long!!!