It is definitely worse to get fired as that may hinder you from getting another job. You should always try to leave jobs on a good note, not “burning any bridges” as the saying goes, since you never know when you might run into someone you previously worked with at a potential new job. It is good that you’re in school as I presume that you are taking classes for the field you’re interested in. Try to consider this job as a means to an end… another job which will be better and which you will enjoy more, since the longer you’re at the job, the better it will look on your resume and the more money you can save in the case you find yourself downsized.
One difficulty you face in looking for another job is working (since that limits the time you can take off for interviews). I would suggest you go to a local employment agency as they will be able to match you with jobs you’re most likely a good candidate for, saving you from wasting your time at interviews for which you aren’t a good match. Also, the employment agency can give you tips on improving your resume and you can ask for advise on interview clothing (they know what employers are looking for so be open to constructive suggestions) and interview tips. It has been my experience over the years that only the hiring company pays the employment agency so it shouldn’t cost you anything for their services.