Could I be pregnant? Have you experienced this also?

Ive been on contraceptive pills for many months now.. Recently I've been experiencing 5 days of spotting a week before my expected period.. My period is supposed to be coming this week but up till now I've had sore and full breasts for 15 days now with dull, mild cramping.. I did missed the first pill on my new pack for this month and took it the next night and had sex with my partner the day I miss the pill.. Could I be pregnant? #pregnancy #advicepls