Should I understand the illness that afflicted me after my prayer for guidance in a financial matter with a legal dispute as a sign to abandon this matter, or should I continue with it to see its future results?

It is not possible to definitively assert a connection between the illness and what you were pursuing. As for continuing with the matter, you should consult experts, for Ibn al-Qayyim said: "He who seeks guidance from the Creator and consults the created, and remains steadfast in his affair, will not regret." And Allah Almighty said: "And consult them in the matter. Then when you have taken a decision, rely upon Allah." And Qatadah said: "No people ever consulted seeking the face of Allah except that they were guided to the most righteous of their affairs."