There is always that possibility. Have you went and got a blood test from your doctor?
After 4 months tests would be accurate by now.there is obviously somthing else going on,i suggest a visist to the docs,get checked out,dont leave it as when you decide you want children,may not be as easy as you think.
thats what ive been woried about. I have a 3yr old but want more
Well my sister got pg almost 7 years ago and she didnt get a positive hpt through out her pregnancy. She did have get positive tests when they did blood tests but that was it!