Does my anxiety and fear of the future, and my apprehension of the consequences of matters, and their causing insomnia and continuous overthinking, contradict reliance upon Allah (Tawakkul)? And what is the solution?

Fear of the future is detrimental to reliance on Allah, so you must trust in Allah and rely on Him. The poet says: "Trust in Allah, turn to Him, and seek His help If you do so, you are the best to be helped." We advise you to consult the counseling section of the website.