Yep, Dena mostly has it.. When you start HRT you essentially trigger menopause/andropause and can suffer the side effects of both. This is fairly normal, it's a sign things are working as expected.
Estrgoen will help with this, but it takes time for E to build to useful levels. I found the first 6-8 weeks were rough, night sweats, hot flashes etc, but after that I had no further issues.