Two days ago i suddenly had a fever, chills, and muscle pain all over. i felt so cold for a while. when i woke up it was gone? my period has been irregular

Without : Without examining you or having more information, it's impossible to say exactly what your symptoms were due to. You may have started with a viral illness which your immune system promptly fought off. If it happens again, or becomes a more on-going problem, you should give your doctor a call. Since it was just a one-time episode, i can't say whether it relates to your irregular period. There are other reasons besides pregnancy that can cause a woman to miss a period such as: stress, diet, excessive exercise or a hormone imbalance such as with a thyroid disorder or polycystic ovarian syndrome. If you are not pregnant and are still worried about an irregular cycle, give your doctor a call. Your doctor will take a thorough history and physical and may run some tests to find out why your period is irregular. Good luck!