Missed pills, no spotting which should have happend. Havin tummy cramps, feeling v tired am i pregna

I missed a pill in week 2 of my 21 days of pills realised 2 days later so took it thn missed another in the 3rd week. Since missing them ive had tummy cramps low down, back ache feeling v tired, very bad mood swings 100 times worse than wen im normaly due on. Im irritable get more emotional than usual. Ive had no spotting due to missing them which you are ment to have. Is there a possibility i cud b preg? Help please