Hypothetical but I'm expecting to be asked. Work 2.5 days a week, small business only 5 in my 'department'. We have had members of staff on holiday for the last three weeks. Boss asked in advance regarding cover for this period and I was able to do what was asked. Fine. Last week boss asked my availability for cover the following day said I wasn't able to do so. Again fine. Now this week we are due to be back to normal however one of my colleagues has suffered a bereavement in the family, therefore is requiring additional time off - which they are entitled to and should definitely take, I wouldnt expect them to be coming into work during the circumstances. Issue comes with covering the additional time off again this is looked at primarily me to cover. I feel completely swamped, dp and I have made some plans for the day I'm being asked to cover. Wibu just to say no? I've been working closer to 4.5 days a week for the past three weeks (also bearing in mind the job started as a 16 hour a week position) - and I am doing a course - through work but pretty much in my own time I have been putting the time in during my evenings mainly.