I had a neg pg test, but have symptoms and a positive lh surge for four days is the pg test wrong?

My hubby and I recently had my mirena (iud) removed fri june 10th and have been using ovulation predictors, they have been positive for four days now but were negative before then. Ive had some cramping, half day of light spotting, afternoon nasea and increased tiredness but when we took a pg test it was neg. Is it possible that Im pregant even tho the test was neg? Or am I thinking about it too much so my body is some how creating my symptoms? We have an older son and my doc says im healthy.