Irregular periods but am i pregnant

Patient: I think i maybe pregnant but home pregnacy test show up negative. i have very irregular periods i came off the pill in march and that was the last time i bleed, apart from a little spotting a couple of months ago. my boobs have been really sore for over a week now and i have been extremly tired and occasionally i get back ache. im finding it difficult to get an appointment at the doctors due to opening times and work.