Etoile, I have never heard of anyone harming themselves with SFQ. However, we each must be our own gardians.
It may be that qigong associated with a martial system would have a higher chance of physical ill effects. However, even then I would suspect it's not the qigong practice itself, but some physical effort performed in concert with the qigong.
Etoile, my advice for you would be to stay with the dizziness as long as you feel is appropriate. While with the dizziness try not to label it try just to experience it. Try and feel the energy within it, without labels of judgement, because our minds can not fully comprehend what is happening. Have faith that the purity of the universal energy that your SFQ practices brings into you will open any blockages and restore a healthy flow. Along the way you may experience the energy in ways you don't understand, but remain confident that you are just in transition.
You are perfection.
Iam2 