Bizarre one here - maybe something simple?

1.9CDTI 150 with upgraded Vacuum hoses (4mm ones), Airbox mod and K&N, 10kboost last weekend, Boost Sensor cleaned last weekend.

noticed been running a bit sluggish in past week after doing work above, doing new EGR this weekend, but plugged DTUK box in this morning and was flying but then started to notice sluggishness low down in revs.
Went over a bump (maybe coincidence) and now reallllllly slow and sluggish - no warning lights on....

Any pointers on things to check??