K., how you respond to this is going to depend on what you want to do. I know that relapses are normal, especially during stressfull events, which includes illnesses. Potty training can be about learning, or it can be about power struggles. If it becomes a power struggle, you are wise to bow out gracefully. My experience with kids is this: you will never make a child eat, and you will never make them pee/poop in the potty. I'll share my story...
My (now 3 yr, 3 mo) DD is also VERY strong-willed. She started potty training at 18 months, in the summer. We let her run nakey-butt and had the potty out wherever she was. By the end of the summer, she was fully day trained and I was feeling pretty smug. Then the weather turned colder, and she had to get dressed. She had more and more accidents. We went from panties, to pull-ups, then she wanted her diapers back. I was extremely sick w/my pregnancy as well as doing full-time daycare for another child. I gave her back the diapers. When she turned two, she started training again. Things went slowly, but well. Then they got worse again. Her sister was born in April, and my MIL came out for a week to help, and while she was here, she potty-trained DD. Since then, we have had a lot of ups and downs. What helps us is for me to try to remember to ask her every couple hours if she needs to go potty. When she has accidents, I try to be calm about it, but also firm that big girls don't potty in their pants. I remind her about all the good things about being a "big girl" and that seems to motivate her.
So, what you could do...
1. Just let her be and she will potty train eventually. This is certainly an option if you don't have the time/energy to engage in potty training.
2. Set a date and take her diapers away. This might work, or it might make her dig her heels in and refuse to use the potty. In either case, if you do this, you should probably be prepared to (calmly) clean up accidents. I've heard this referred to as the two week, $200 method - two weeks to train and $200 to get your carpets cleaned. ;)
3. Set a timer (or just remind her every hour or two) and tell her "It's potty time" whenever it goes off. We tried this, and it had mixed reviews. It was helpful to remind her, but to make her sit on the potty just made her stubborn.
I would think about why she is having accidents. If she is having a hard time figuring out that she has to go until it's too late, it might help to keep her potty handy. You can slowly move it until it winds up in the bathroom. If she gets easily distracted on her way to the bathroom (my DD), you might need to walk to the bathroom with her to help remind her about where she is going and why. No matter what, don't turn it into a power struggle. Best of luck.