I have this feeling that if you just left in 10 days as she is asking, you would not get any of your deposit back. So you lose. If she takes legal action, you will probably lose as well but at least make her work for it and it will give you a lot more than 10 days. Not sure about the legal costs, but you can stop paying rent now and keep living in the apartment while she takes the legal action which will take some months, so whatever costs there are of the legal action can be recouped in some way by your squatting.
But this is a last resort. I would still try to seek some amicable solution without legal action. I think the best option now is to apologise very nicely, tell her you wont do it again, you realise your mistake, blah blah blah, and become a good tenant. I think its in her interest to give you one last chance.
If she really doesn't budge and wants you out, just tell her OK but it has to be done the right way, the contract doesnt have a break clause so it must be done through the legal process, politely inform her the action will take months and not 10 days, and you will be withholding any rental payments during this dispute period pending the results of the legal action. But really do your best to avoid this.