Irregular periods, eating disorder, no period for 1 month, pregnancy symptoms

Hi, I m looking for some advice in regards to my menstrual cycle and symptoms ive been having lately. I have always had an irregular period, not actually starting to I was 21 due to an eating disorder however I am at a healthy weight and live a relatively healthy lifestyle now. Anyway I haven t had a period in over a month, which is not that odd for me, however I did have some irregular bleeding , v light lasting for one to two days. I took several hpt when I suspected I may be pregnant but all came back negative apart from one which had a slight positive. I just left it at that and thought nothing more of it but now I have sore breasts, I m so overly tired all the time and my mouth is dry. Ive also been more emotional than usual so I just assumed that my monthly cycle was coming. Still nothing! I took clearblue hpt a few days ago, 2 of them and they were both negative so I m really at a loss as to what to think now. We are not trying for a baby And I don t think I m under any more stress than usual so if you cud offer me any advice I d be very grateful.