On bc for a yr & we use condoms but my period hasn't shown up on my placebo days. took a hpt & it was neg. is it normal to miss a period??? help!

Very common: It is very common to not bleed during the placebos on birth control pills. Especially with low dose pills there is very little buildup and may be no bleeding at all. If you have not missed any pills during your cycle, not taken antibiotics, and not had vomiting (vomiting after taking your pill would be missing that pill) you should not need to worry. If it happens next cycle see your gyn.