Well, a good voice coach will help make sure you aren't pushing too hard, and a speech therapist can guide your progress to your goals, but a doctor can rule out anything medical, so it's a great place to start. Wasn't sure what your financial/health care situation is, so I just meant to consult who you could. Please don't panic, there's nothing going on that's going to be a serious issue.

As far as over doing, I do need to give the disclaimer that I'm not a pro of any stripe, I've just been around people going through hormone therapies, and musicians. The partially occluded exercises can generate more pressure than you'd think. That pressure can strain the throat some, as well as pushing up through the eustachian tubes.

So, you've got pressure and vibration hitting some small, sensitive areas. Usually, people will feel strain in the throat, above the vocal folds, if they're pushing the air too hard, or otherwise straining the areas involved, and back off a little. But it can still cause some ringing or other artifacts in the ear, even when done perfectly.

In my limited, non professional experience, it can be really hard in the absence of someone that is trained to know where the point is to back off. Even when done perfectly (and you probably are, they aren't difficult exercises), they can be done too often or too long. However, the schedule you're describing shouldn't be causing a problem.

Tbh, high blood pressure, even if it isn't medically significant levels, is a more likely cause of the headaches after doing the exercises. The ear issue, I've seen happen often enough from pretty much any vocal exercises, I would be surprised if there's any kind of pathology involved at all. I did some of the ones you're talking about while I was typing this up, and my ears are kinda tingling inside.

The schedule you describe is pretty much on par with what I've seen speech therapists recommend, so I doubt it's that. Most likely this is just a combination of the bp and the vibration/air pressure causing a stronger affect than normal. Again, don't panic. Worst case scenario, you get blood pressure meds and keep going as you are, maybe with a little less oomph as you push the air out.