Energy level down after increasing protein

Is it because you're eating heavier foods, like meat? The more meat I eat, the more sluggish I feel. But soybeans and tuna don't seem to bug me.

Hmm. Might be worth a blood work up if that's feasible. Maybe anemia?

I found that too when I had lots more protein in my diet, i've since added more carbs/less protein and find my energy levels alot better

No numbers, closed diary, who knows.....

Rabbit starvation (excessive protein) is a thing.

Less carbs can make you a little more tired. At least until your body adjusts to it (it will easily start using fat and protein for energy when out of carbs, that's no problem, you'll just feel more tired until your body gets used to it).

Less carbs can also mean less sugars too if you lowered sweet foods that you were eating. Less sugar in your diet, means your body isn't getting the sugar rush as much as it did before, hence making you feel like you're a little more tired.

Out of the macronutrients, protein is the most 'difficult' or effort consuming for your body to process and digest. No idea if its possible or not, but if increasing your protein intake by a large amount (like doubling it or something, from 60 to 120g / day if not even higher), just the extra effort your body is regularly putting up to digest your food might make you feel a little tired, till it gets used to the changes.
Of course on that point, I could be talking out of my *kitten*, and massive sudden increases in daily protein mightn't even be possible to make anyone feel tired in that regards. But it seems like something possible to me, especially if what you were eating before more protein, was something like simple carbs.

you're doing strength training twice a week. yoga once a week. And purpose walking (as opposed to any walking you do in daily life like around the house, or at work) up to nearly 10 miles a week. On top of I would guess a 8-10 hour job, and then general house and garden work possibly.
Are your calories set right to maintain weight (ie. very slowly lose a little fat while building a little muscle, but the scale remaining mostly the same), as if they're calculated too low due to the amount of activity you're doing, and you're actually losing weight because of that. Just the small deficit, combined with doing all that activity, might just be burning you out a bit, so you'd need to rest for a few days / a week, or change up some of what you do.

Also keep in mind, that a proper strength training workout, could just leave your body fatigued for over a day or so, while recovering, even if your diet and sleep and other activities are all good. So that a more sluggish body might just make you think you're tired overall.