Two choices, either be dishonest and ring in sick for another week and hope the doc will sign you off or go in Monday, explain what's happening Weds/Thurs, apologise for the less-than-ideal situation but take the days as unpaid leave. At least then you're doing the right thing by your employer and you can't be caught out.
I've been signed off work for 4 weeks due to illness, am hopeful of returning on Monday. On Wednesday I have to attend court and I have just been offered a job interview on Thursday. I don't know what to do, feels too soon to get even more time off.