What Causes Delayed Periods With Tender Breasts And Extreme Tiredness?

I have mot had a period since oct 13th 2010. .I was 50 in jan so ignored the absence of periods thinking I was v lucky to have had menopause so easily and symtom free. periods were every 28 days like clockwork. I am now feeling movement and although I have experienced other classic 'pregnancy ' ?? symtoms tender boobs, nausea extreme tiredness gone up 2 dress sizes , felt flutters for a while and dismissed them as gas, but now deifnite movements I have done 2 urine tests one day after the other last week and both negative. .what is wrong I feel pregnant so could it be a tumour??