HPT results

How many days past your predicted period did you guys get BFP's. Also does anyone know if there are things that can mess with your results (alcohol, smoking, certain foods, taking a test at a certain time of day)
-cycle is usually very regular (about every 29 to 30 days), I'm on day 32 and all negative hpt. Sore breasts, headaches, mild mood swings (more weepy than anything), very fatigued, and have had mild nausea.