Kindly pursue the MA (Economics) course immediately, may be, after you complete one year of the MA (English) course.
Please do note that Economics will open any number of doors, much more than what you can earn, if you are an English teacher. Yes, English teaching will always be in demand for centuries, but Economics is something that has a very wide application.
The present experience may not take you far. You should jump to another school in the secondary section, after English. If the school is a residential school, by run and managed by a large group like the TVS, Mahindra and Mahindra or the Adiya Birla Group, or even the JK group, even in locations like sugar factories, cement factories and so on, they will provide you accommodation, and also sometimes free food, apart from salary.
Forget for a moment that you will be cut off from all human civilization and the external world, for say, twenty four or thirty six months. This experience will help you to park yourself, get the MA (Economics) and then plunge into research. Please do note, only Research in Economics will take you so far. Combine this research with a doctorate from a neighboring University.
Try for research roles with the Indian Institute of Management or the IIM, Bangalore, where superb facilities exist for research into social and economic problems, or issues. Once you get in, enroll for the Part-time doctorate degree with say, Gujarat University, Ahmedabad, or the Bangalore University.
Please do note, such an experience may set you back in terms of salary. Do not bother. Those thirty six months, when you do your doctorate, will be highly value adding in terms of experience and then you can automatically get employed with any good University, or even pursue advanced research abroad.
Please do note, based on first hand experience of having worked in one of the IIMs for a while, I can safely tell you that any short term loss, is a huge long term gain. A gain that will take you abroad and change your fortunes for ever.
Even while working, concentrate on publishing research papers, in collaboration with the professional professors, who are simply world-class. For example, you can find professors at IIM, Ahmedabad with two hundred research based publications in their name, in international refereed journals!! Most of them are consultants to World Bank!!
So, this is the career you should choose. Be patient, but make all moves suggested. Do not give up the MA( English) course, as this help you to play a dual role, like a hero in a Tamil movie -- a teacher of both Mathematics and English!!
Jokes apart, please do place your wagon to the pole star, on the lines suggested. You are sure to be a winner!!! Please do note, the doctorate in economics is the ultimate destination for a very eventful career.