Question: Not looking forward to being disappointed

So in 2009 ive been diagnosed with Endometriosis. Got married in Dec 2014 and we've been TTC ever since. My period came every month but was very irregular last year. Since 2016, its been back to the 28 day cycle. My last period was on 13 April 2016. My breasts are sore and tender, my back is killing me and my period a 7 days late. Could i be pregnant? Hoping to buy a test by this weekend (21 May 2016) if my period still didn't appear.