Tachycardia and stronger palpitations in the first two days post-injection is a known pattern - vasodilation and the autonomic shift overlap at that window. BP improvement is the more consistent long-term signal; the palpitation response typically narrows by the second or third injection.
The carb adjustment for sleep is the kind of thing most first-time guides miss - starting low carb while adapting to a new medication adds more variables than it's worth. Getting protein in consistently is more useful than restriction early on.
Water, magnesium, fiber, and light walking covers the main levers for early GI management - most people find constipation settles within the first few weeks once the body adjusts to slower motility.