AF is super late and I keep getting BFN's

Recently my husband and I have started ttc again. We tried for over a year from October 2010 through December last year. We quit because we got a cruise to Mexico for Christmas and couldn't use it until September. So, we stopped trying and I also stopped tracking my cycles. While on the trip we started ttc again. We took the trip around the 23rd and I know I got AF about 2 weeks before we went on the trip. After the trip AF came October 9th, so I'm not quite sure what my average cycle is anymore. I've been looking at my past cycles and the shortest was 27 days and the longest was 36 days, with the average being around 31-33 days. Well as of now its 36 days and I'm not having any of the normal symptoms of AF coming. No sore bb's, no cramping. I've taken 4 99cent store pregnancy tests the most recent yesterday and they've all been negative. Today I'm suddenly feeling nauseous and I can smell my cats breath who recently has been acting strange. She's always wanting to lay on top of me constantly(like all day if I let her), when normally she will lay near me but will run away if I pet her, its almost like she wants to be treated like a baby. I keep having to push her off of me because her breath is fishy and makes me want to puke, but she keeps coming back. I've had my cat for 5 years and this is something I've never experienced with her before. I don't necessarily think I've tested too early so either I'm not pregnant or all of those tests are defective, but I'm definitely wondering because its already 36 days and I feel like AF isn't coming anytime soon both mentally and physically. What do you guys think? Any feedback is greatly appreciated.