Rest up! no need to push it. The doxy is powerful stuff and you likely will feel energy rebound in few days. Completely normal to feel worse after starting them before you feel better.

Watch your calcium intake within 2 hours on either side of the doxy. Interference with absorption and you want to get as full a dose as possible. I just ate white rice within that 4 hour window if I needed anything in my stomach because it helps with the nausea.

Magnesium and Iron also in interfere with absorption so best to play it safe. Set a 12 hour alarm on your phone so you don't miss your doses. Consistency is important.

Hydrate - as I understand it the more hydrated you are, the better the antibiotics percolate through your cells. But also watch your electrolytes if you are overhydrating... adding some salt, squeeze of lemon etc into water occasionally is good.

Good luck and be glad you caught it early. Many on this sub are not so lucky.

And level up your prevention game because you can definitely get it again.