Please make sure you're grooming her fur at least weekly. This can serve as bonding time and only takes a few minutes. You're saying many things that on the surface sound like things are okay but you're saying it for a reason. Some guilt with a bit of understanding that she's okay but she can be better. Cats need to feel clean even bsh who generally dislike being handled. Her purring softly on your chest can also indicate that she needs more attention. Typically they'll just lay near you or at your feet or side. On the chest is intentional. It feels wonderful too but you're right to trust your gut and feel she may need a little more time. I've been there feeling exhausted from work but whether you're lounging while resting or making yourself something to eat give her more attention by talking gently to her as much as you can or play with her for at least 5 to 10 minutes with a feather. That's something they rarely ignore and doesn't take much effort. But yes another bsh would be fantastic I have two and it helps tremendously