I just find it unfair in my part that i have invested my time, effort and money for the job offer yet they will let me go in the middle of my application. They should have not given me the offer in the first place if they are in a hurry knowing my current situation. Anyways, thats just my frustration right now.
Yes, it's unfair, and there's not a thing you can do about it. Try to set it aside.
It might be worth considering how you will feel if the work visa comes through in time, and you end up working for this employer.
There is no advantage in applying for another visitor's visa until you know if you still have a job offer. If the employer withdraws the job offer this week, as she has said, you still have plenty of time to tell INZ, and get your application for the visitor's visa in before the present one finishes. Like I said before, INZ will automatically give you an Interim visa to keep you legal, as long as your fresh application is lodged befor the present one runs out.