Hello and welcome to this wonderful community!
As you will continue to hear, everyone heals at their own rate. My surgeon pronounced my sternum healed at about 5 weeks (placed his open palm gently over the site and had me turn my head a full 180, shoulder to shoulder) but I still felt uncertainty (wish I hadn't reached over the kitchen sink to slide a heavy window shut..... click, click, tweak, ouch went the sternum) so I babied myself and avoided lifting or stretching out like that (as in lifting a suitcase up into the overhead bins -- wouldn't want to rush that) as long as I could. Perhaps checking your bag is an option?
For me it was the lack of resiliency. You start off on whatever small enterprise it is, then, so much sooner than you want, you run out of energy. There is no reserve. It's the darndest thing! You simply must listen to your still-healing body and take a nap! or at least stop for awhile. I don't think we really know if it's the healing body or the residual drugs (and oh, it's a very long list of drugs they give you during your surgery and hospital stay) that cause this effect. Apparently, the body does not fully cleanse itself of the drugs for almost a year (hard to believe). So I was able to devise a healing lifestyle by doing things in small spurts. That is what worked for me. Because of that, I would highly recommend that you work from home as long as possible. You may find you can work from home fairly soon! (be sure to have some checks and systems in place to monitor the accuracy of your work, though..... you will think you're thinking fine, but you will be pretty spaced out for awhile!)
Most of us think that the pain will prevent us from doing things. In fact, many of us find that we experience very little pain! But try to remember the worst bout of flu or fever that you ever had --you ached all over, not really painful, just soooooo tiring and uncomfortable. THAT's what this is like. It gets better every day, but then sometimes, out of the blue -- wham! you're back to feeling it til you stop and rest. I think it's our body's way of telling us we're not letting the healing process occur. You really have to honor the healing process. In the long run, I think it helps to kind of give in to it.
I know you asked for numbers, but I thought these descriptions might be helpful.
Best wishes.
Marguerite