What Causes Light Periods Along With Sore Breasts?

Hi.. I am 24 yr married gal.. my husband is working out of town.. he came on19th feb. And my date is also 20th. So I take the date extending pills from 13th..bt my frnd told me its not good for health. So I stopped taking it on 18th. Me and my husband had made up unprotectedly on 19th and 20th.. i take i pill on 21st... then I got my periods on 22nd. Bt its not like I am having every mnth. Its not that much heavy.. This mnth I got my period on 28th( 5 days late).. and my breast are becoming little bit hard, little bit painful since 20th... Am I pregnant..? Or what it is..?