TTC and need advice!

My husband and I have been trying for a year and a half. I was diagnosed with PCOS 4 months ago. I started Metformin and I have finally started getting my periods again. 4 weeks ago I came down really sick with flu like symptoms and after battling that for 2 weeks I was hospitalized for 6 days with a stomach infection and pneumonia. While I was in the hospital I didn't take the Metformin and when I was released they told me not to continue taking it. I have been home now for 2 weeks and I am now 9 days late. pregnancy test is negative and blood test is negative. I am still very sick and unable to hold down a lot of foods and the pneumonia isn't clearing like it should. My question is am I late because of all the antibiotics, or because I have been off the metformin  for 3 weeks now. Also you read those stories where people are weeks late and still get negative results but are actually pregnant could that maybe be why I'm late. I know that is probably a slim chance but one can only hope. I just want it to happen so bad. Please help!