For certain reasons, will I be eligible for unemployment benefits if I resign?

Generally, you can't collect unemployment for leaving a job voluntarily but sometimes you can if you are fired for unjust cause. Now that can be difficult because you have to prove the injustice and your employer can fight you on getting the unemployment. I would do your best at keeping your job happy for now as far as taking days off and whatnot but if you feel you're being treated unfairly, take action. Many employers depend on their employees lack of knowledge about their own rights. Who's actually made these threats about firing you? Is it your immediate supervisor? Talk to this person about your concerns and see what you can find out. Ask if there is anything you are doing wrong, and, if so, what can you do to better it? If this this is ineffective, go up the chain of command to the next person in charge. Show them you're serious about your job and want to keep it. If you make all the efforts and still end up getting fired, contact your state department of labor and find out more about your rights and what you can do. In the mean time, just to be safe, look at some other job opportunities and see what you might have to fall back on if you should end up losing this job or decide to leave it.