AF symptoms after faint positive

A little worried and hoping someone can reassure me a little.

Been having a few faint lines but don’t seem to be getting any darker yet (last 3 days).

Today have had nausea, lower back ache and dull AF type stomach cramps along with slight brown/pinky discharge. Am I likely having a chemical? Or is this normal. Can’t remember this with my daughter and have previously had an early miscarriage. Would be around 4 weeks only. Thanks x