I'm sorry you find yourself in this situation. I suppose talking it out is not an option?
An IUD will probably show up. How about an implant? It's placed under the skin on your arm and so it may escape a doctor's attention. Although I'm preety sure you don't have a period for some months, so that may not be a good option either.
Other than secretly taking the pill, I have no idea (maybe go to a totally different doctor to get it?). You could try doing the natural awareness method and avoid sex on the days you're fertile, if that's an option, but it's likely your BF would be aware of what you're doing (it requires mesuring your basal body temperature every morning) and would want to use it for getting pregnant instead. You could learn about the cervical mucous method, which however is not that reliable unless done properly and it takes some time to learn.
How about you make a deal with your BF that you will take BCP for another year and then go off to prepare your body for pregnancy, which would ideally take a year

- it's really good to flush the BC out of your system before getting pregnant, no matter what anyone says.
Also, in case all else fails, do some research on what to AVOID when trying to become pregnant (like hot baths etc.) and do some of it (that doesn't endanger your health). It may not work at all, but at least hot baths don't sound so bad.
I hope everything turns out all right.