Hi. I have completed my MS lab work recently and am looking for a full time job. I want to get some practical experience and save some money before starting my PhD. I've been offered a job as a lab demonstrator which has the requirement of a BS degree. I feel like I've wasted 2 years of my life doing this MS and I should have gotten this job 2 years ago. Lab demonstrator and helping with bachelor programs is great when you're doing it part time with a PhD but I'll be doing it full time and that's what'll show up on my CV from Nov 2018 to xyz.

Hi. I would quote a reply to a similar post before. Some PhD graduates do full time lab demonstration jobs. You have not wasted two years doing Master. If you keep looking to things like that, your life would be like a hell.
Another point. Do you have currently a PhD offer that would start in a later date? If not, do not think of the job as a temporary one because this will make things more difficult. Let us call things by their real name. You want to do a PhD, apply now for PhDs. Meanwhile look for a job you would be a bit happy to do it and accept the fact that you may get or not get a PhD position.
One thing you forgot to add to the post. I am now "xx years old" and by this age I should have received a Noble prize (just kidding).