What Causes Delayed Periods After Missing Intake Of Birth Control Pills?

Hello. I have been on the qlaira pill for about 9 months now. Everything was going fine until this month. I missed pills day 14,16,18,20,26,27 and didn t use any protection. I stopped taking my pills after I missed day 27 and haven t taken them for a week now expecting to come on period before starting new packet. I haven t come on. I took a pregnancy test 2 days ago came up negative. Is it the pills that are stopping my period or could I be pregnant? My period are always regular and I should of came on 7 days ago. I have been getting weird pains in belly don t know if that s anything. Many thanks.