Breastfeeding, spotting, and nausea... help!

Would a test be positive by now?

I had some spotting on 6/28- my period isn’t back yet.

I’m having weird headaches and nausea and some other gastric distress. Had what felt like a cold on and off the last few weeks which was what happened last time.

Took a cheap Walmart test this morning that had been in my car for a month or two and it was negative. Should I test again?