When you’re facing a horrible, trying event in your life, how do you know if it’s a trial or testing from the Lord or not? I know that He allows us to go through things for various reasons, for example, to draw us closer to Himself, to grow as children of God, etc. But how do we know when it’s not from Him? When that instinct is telling us, no this is not right, how do we know if that instinct is correct and from the Lord or if it’s just selfish human nature trying to steer us away from what the Lord wants for us?
The theology upon which your question is based is flawed. While you still hated Him, God loved you enough to send His Son to die for you. Do you really believe that now that you love Him, He’s going to arbitrarily put you through trials to make you into a better person? For what? He already sees you as a new creation who is as perfect as He is. (2 Cor. 5:17, Hebrews 10:12-14) And consider this. Why would He waste a lot of time trying to make you into a slightly better person now, when He knows that one day soon, He’s going to make you perfect forever. Remember also that Jesus said He came so you could have an abundant life (John 10:10), not a miserable one.
It’s a popular thing to blame God when things aren’t going well, but the fact of the matter is that He expends a tremendous amount of effort to protect us from trouble. In my own life I’ve found that the hard times I’ve endured have been caused either by my own actions (consequences of bad behavior) or by the fact that we live in a fallen world where bad things happen without cause. The Lord has proven Himself to be someone who turns my lemons into lemonade by making things better than I have any right to expect, not someone who looks for ways to test or try me.