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Due to messing up of the pill taking schedule, there are high chances of pregnancy. When you miss two pills in a row, you are no longer protected in that cycle of pills. When you miss two pills in a row, you should use additional protection (condoms/spermicide) while having intercourse and continue the rest of the pack as usual.
Your current symptoms do suggest pregnancy. Sometimes urine pregnancy tests can keep showing you false negative results due to less concentration of pregnancy hormone (HCG) in urine during early pregnancy.
Visit your gynecologist for an examination and a blood beta HCG level test (it can detect pregnancy accurately than the urine pregnancy tests as early as 11 days post conception). Stop your birth control pill use if found to be pregnant.
Take care.