12 days late 6 negative HPTS HELP

Hubby and I are trying to conceive our first! So far my period is late by 12 days, I've taken 6 tests (1st Response, Clear Blue, EPT) AND THEY'RE ALL NEGATIVE. I'm not so sure what could be going on, hence this is my first baby I'm hoping for. If certain symptoms help, I've been experiencing headaches, bloating, nausea here and there but no vomiting, it's uncomfortable to lay on my stomach and I get tiny cramps or mild cramps. My last period was Feb 19 and I noticed I spotted on March 13 a reddish brown color. Discharge is a little thicker but white and odorless. We're really hoping I am pregnant but we're so confused to why I'm testing negative with no period still. Has anyone experienced this at all and finally came across a positive test? I've been googling answers for days but all I read is other users' questions as an answer. I need stories, recommendations, guidance, etc etc! Please and thank you.