There are several variations of this story; here is one:
A man fell in the ocean and he couldn’t swim. When a boat came by, the captain yelled, “Do you need help, sir?” The man calmly said, “No, God will save me.” A little later, another boat came by and a fisherman asked, “Hey, do you need help?” The man replied again, “No God will save me.” Eventually the man drowned and went to heaven. The man asked God, “Why didn’t you save me?” God replied, “I sent you two boats!”
Sometimes in our walk with God, we don’t see the obvious answer or solution that is right in front of us.
Religious people over the years have tried to explain how we are supposed to know if what we think God wants us to do is actually what God wants us to do.
I think the best answer is to pray about it and read the Bible. If you still have doubts, seek counsel and guidance from a fellow Christian or leader in your church.
Plus, be on the lookout for boats.
Trust in the Lord with all your heart and lean not on your own understanding; in all your ways submit to him, and he will make your paths straight. –Psalm 3:5-6