Based on what you write, that you have previously established that similar hargashot are associated with clear discharge, they do not affect your niddah status.

The question remaining is whether you have heavy staining on colored underwear (which does not make you niddah) or a light flow (which may, depending on its color). This is a difficult distinction to make, and is to a large extent subjective. Seeing blood exit the body is defined as a flow. Having enough discharge to need a pad is a common rule of thumb. Based on your description, it seems that you are not quite at the flow stage.

Even when staining does not make a woman niddah, we advise abstaining from relations until about a day after it has subsided. This is a precaution against having a flow start during relations and not a strict halachic requirement.

Please get back to us with any follow up questions.