Being pregnant alone can cause this! But bending over will cause it, happens to me all the time. I know the feeling of not being able to take anything while pregnant, its horrible...maybe you do have a sinus infection hun, see your doc about that! when i was pregnant, i had a bad cold, lasted for 3 whole months, and FINALLY i went to the hospital, and had to be given antibiotics for 3 days....i understand the doc's concern about given med's while pregnant, BUT they also need to understand, that being that sick and uncomfortable, ISNT good for you or your baby....try and take it easy ~
Sinus conjestions gets worse when bending over and cause headaches. Most people worry about brain tumors (I know I have) but remember the headaches associated with them generally cause vomiting and nausea and normally have other symptoms too.
I had back to back colds with a sinus infection (never went to the doctor). I had ongoing headaches and ear pain for about 3 months but now has gone.