thankyou for posting your question.
There are many reasons why you can skip a period - apart from beig pregnat. It could be due to thyroid
malfunction, cysts, high levely of prolactin
and hormone which induces breast feeding). Seeing as you have a few other symptms which might be an indication for thyroid problems or ovarian cysts - the only way to find out is to pay a visit to the GP or Gyn & OB.