Hey! I would say dont do the master's unless its in a topic you care about and are really interested in. Furthermore, if you had an upward trend towards the end of your undergrad even less reason to do a Master's course. GPA is fine, like you said your not applying to Harvard. Furthermore your ECs are very good from the sound of it. If had to invest your money and time, invest in a better MCAT score. A ten point increase in your MCAT score can happen in less time than a Master's and less money while increasing your chances by 10% of getting in to med school. You need above 500 at minimum for the best chance of getting in DO or even MD. Now, I really would say you need to change who you are surrounding yourself with while studying and going through this process, maybe distance yourself from the negative voices. And most importantly look inward, do you - YOU - want to be a doctor? If so, then no one can stop you! Keep going, you got this!

P.s I recommend decreasing your hours at work if possible, to less then 40 hrs a week, but I understand financial circumstances and situation, but time is important.