I think it would be a bad idea to give up your source of income in the hopes that you will find something better as soon as you graduate in August. What if you don't find something right away? How long will your savings last you?
Why not start looking for a paid position in your desired field, similar to what you would be looking for once you graduate?
Cam u volunteer and keep your job?
See if the internship can be worked around your work schedule. Or if you can take a sabbatical. The VOR in me says keep your job. But I'm all for people pursuing their passion.
make the change while you still have the energy and inclination. once complacency takes hold its difficult to wiggle free. Im preparing to make a move myself. GL to you