Help!!

Kenzie
So The last time I BD'd was 2 weeks ago, then again Halloween, and Monday. (Was ovulating both days) the past 2 days I've been extremely neasous, lightheaded, throwing up, and have extremely bad heartburn. I took a test tonight and got a BFN, I'm just concerned if I should wait longer or if this could just be me getting sick. Keep in mind, I have extremely irregular periods. 
Below is the test I took tonight: