Hi, and welcome to these boards!
First of all I'd like to offer my condolences on the death of your son.
It's wonderful to hear, though, that you are TTC again! Well....I'm no expert on PG, but seeing that nobody else seems to have answered, I'll give it my best shot.
I know that after giving birth women bleed for some time. I've always heard that it's around 40 days, but I'm sure some of the other ladies here will be able to give you some figures. I have also heard that it can vary from woman to woman.
So...if your last AF was 53 days ago (now 54), you could very well be ovulating. Count 40 days of bleeding and 14 days from then until ovulation day. This ties in with the creamy mucus you describe. Some of the other symptoms could also be ovulation signs.
The other possibility is that you're PG! Maybe you ovulated early on and got PG without realizing it! If your previous PG test came out negative, then you may be "resistant" to the HPT'S. Go to the doc and get a blood test instead.
If it's negative, wait for AF and start charting temps, etc, to pinpoint your most fertile days. You're welcome to join us TTC ladies over on the TTC Buddies thread! Just jump in and introduce yourself!
"I am not young enough to know everything."
- Oscar Wilde (1854-1900)