Feel so sick!! Need opinions please :-)

Well I do not know how many DPO I am as I have PCOS and with irregular periods and inconsistent ovulation, I haven't tracked anything this month - needed to relax before we see FS next month. Anyway I am having incredible cramps, my back is killing me, headaches galore, really tired and my moods are all over the place. My AF if comes on time would be due in 9 days so of course when I took a test it was negative :-( anyway ladies I have this afternoon been sick a handful of times and this is most likely to just be the start of a migraine but am I ok to take painkillers or sickness tablets if I actually I could be pregnant?