Uti :( is my antibiotic safe?

My dr prescribed macrobid and of course I am nervous to take anything especially in these early stages! I am about 7.5 wks! Anyone taking this antibiotic before with pregnancy? I know the dr told me it is the safest one on the market and the pharmacist assured me it was safe and she only gave me hthree days worth to get rid of the infection but I am still so hesitant I dot want to neglect symptoms either and make the uti worse I am so last as to what to do! I've been pushing fluids and chugging cranberry juice but not sure if it is enough!