The I before E except after C rule has so many exceptions that it is nearly useless. I have seen many people who frequently recite that rule misspelling words that do not conform to it. There are numerous exceptions, and exceptions to the exceptions.
While it may help you spell a lot of words correctly, it can also have the opposite effect for many other words, even if you consider common exceptions, pronunciation, and other factors.
Some people argue that this rule should be ignored, and that we should stop teaching it. I agree with them, and would recommend that you forget this rule altogether and just try to remember the correct spellings, using spell-check or looking them up as needed.