What Causes Delayed Periods,appetite Loss And Stomach Bloating?

Hi I'm on loestrin 30 and have been for about a year or so now and have always had a period during the pill free week but last month I didn't take a break and I'm now due for my period about 4 days ago but still haven't come on. I have been having sexual intercourse. The last few months I've also lost my appetite and have been very bloated and not needing the toilet as much as usual. I've taken 3 pregnancy tests and two have came up negative. Is there any chance I could be pregnant?