If i miss birth control pill in the 1st week & take it 6 hours late &dont use backup for 7days can i get prego?

Okay so a few weeks ago i wasnt home @ 5:45 when i was suppose to take my pill, so i took one at 11 later that day! & we did not use any backup method (not even withdrawl) for the next 7 days. can i be pregnant? or if i have unprotected sex the day before i stopped taking my pills can i get pregnant? Lately at work ive been getting dizzy, headaches & stomache pains. My last period was also different then usual it was 4 days of regular flow & follwed by 3 days of sometimes pink more brown spotting!! but i had no pms symptoms or cramps which is unusual because i get both to the extreme along with a heavy flow! May i be pregnant?