I have been taking doxycycline now for two days for a bad sinus i...

I have been taking doxycycline now for two days for a bad sinus infection.I feel the need to take the medcine near the time of dosage due, I have this nervious feeling within 15 min. and my heart speeds up for about 20min.I have the sick feeling on/off during day and dizzy right after taking it if I move around to quickly. I have migraine frequenty so I am unable to take any other meds to help this until I am finish with this.I am during my period and it seems to have increased the flow. But heyone good thing, I am feeling better with the sinus infection.