Late period

I'm a couple of days late for my period, I religiously take my pill every morning as soon as I wake up, not missed one for months and months. I'm a couple of days late but still experiencing pms symptoms... back ache, sore boobs and a sicky feeling.

I have recently been diagnosed with ulcerative colitis after a small flare up... could my frequent toilet trips (loose number 2s) cause my pill to become less effective?

Any help or advice is much appreciated. 😊