Urgency to empty bowels

Hello
My first message on here, I hope somebody can point me in the right direction.

Not always, but frequently, perhaps once a week, once a fortnight at the outside, around 30 minutes or so after eating I get really gripey pains in my left lower abdomen and need to get to the loo quickly, generally I have what I can only call explosive diarrhoea..........sometimes I feel I've finished, but then wipe and it kind of makes me want to go more.  But it is a real urgency - I worry how I would manage if I wasn't near the toilet!!!

Other than that I have what I think are generally normal bowel habits - I can open my bowels twice daily, maybe once a fortnight may need to take a Senokot if I feel a little sluggish.  The other thing I have noticed is that sometimes I have undigested food in the pan after going.  No blood.

thank you for reading it and thank you for any suggestions you can give me.