supposed to get my period on placebo pills...

Hi,
Welcome to ehealthforum,
Not taking sugar/placebo pills does not affect periods (since these do not contain hormones). You can have lighter period or missed period while being on hormonal contraceptive pills. However, chances of contraceptive failure resulting in pregnancy cannot be ruled out. It is also not necessary that all women should experience symptoms suggestive of early pregnancy (few women do not know they are pregnant, unless they miss period or get confirmed with pregnancy test). If pregnancy is suspected, visit your doctor/gynecologist at the earliest for thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately). If pregnancy gets ruled out, further evaluation would be done to look for the underlying cause for your missed periods. Treatment as appropriate (based on examination findings and investigations results) would be started to help you regulate your periods. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Take adequate rest. Drink plenty of water. Maintain healthy diet.
Take care.