cherraven, maybe you should take a day off and start a lower dose. Contact the providing physician tomorrow.
The palpitations and the headache can be alleviated by starting hydrated, taking tea or coffee for the caffeine and having something a little salty.
Parathyroid hormone pulls calcium from the body to trick your body into thinking you have bone loss and need cells that replace bone. But the calcium (also) dilates the blood vessels, making the heart beat much harder to make the blood circulate sufficiently in the expanded blood vessel, causing palpitations and dizziness. The calcium also dilates the blood vessels in your brain which, according to the endocrinologist I see, is the single cause of headache following the injection.
None of this is advisable at night when you may experience nocturia with dizziness and low lights incurring a risk of falling.
These effects may go away, as reported here, after days or weeks.
I hope the medication works for you, if it doesn't you might try Forteo which is a lower dose and said to be a little less effective than Tymlos.