Should I take on a new role when I'm already unhappy working for the company?at would you like to ask?

I'm currently a receptionist for a real estate agent earning $12.70 an hour. We are understaffed and the Property Management Dept has asked if I would like to be trained to fill in one of the vacancies.

I am not sure whether I should take on the bigger pay packet for some reasons as followed...

I started over a year ago in my current role and have become very negative, clients and colleagues which I won't blame them for my low outlook on life as I am responsible for my emotions but they have significantly contributed to it.

I don't know whether I should be starting a new role within a company I'm already unhappy with, the PM dept is always either understaffed so everyone is doing everyone else work/ over worked/ stressed/ swearing when I pass phone calls onto them because they dislike the tenants/landlords or complaining they are underpaid for the work expected of them.

I have been looking for new work for about a month now and haven't had any real bites, I am looking for better pay but I'm not sure if I should sacrifice my happiness for it.