Any help? Please ?

I'm 20 days late for AF. My cycles have been every 28/29 days since coil being removed in June 13. 
I had a slight bit of spotting at 4days late and bad cramps leading up to it (felt like she was coming). Took a test the next day and bfn.  Took a test 3 days ago and still bfn. Just curious if anyone has received a late bfp? Is it possible to get a late bfp even? 
When I had my daughter I didn't find out till gone 9weeks., but I wasn't ttc so it didn't occur to me I could be preg.  
Doctor didn't seem concerned when I rang and spoke to them, just fobbed it off as "it happens sometimes" I feel different, have major bloating and quite gassy. Any help appreciated... Or similar stories. ☺️