I don't think that there's any cause for panic. The GE results were obviously disappointing for her and the Tories, but she won over the DUP quickly and easily. As long as most EU leaders think that the "4 Freedoms" (free trade, capital flows and free movement of people) are inseparable, her hard Brexit line seems the only reasonable strategy for Britain.
And as for her health: At 60, she's younger than she looks and while diabetes might be troublesome at times, it's a managable chronic condition. A PM's job naturally comes with a bit of stress, and that's kind of unavoidable, but as long as she and her doctors look after her health (and keep her blood pressure etc. under control) she'll be fine.