This is no dumb question. In fact, it is quite a difficult question.
I think the first thing to address is this person’s calling. I have served on several discernment committees for person’s wanting to go into ministry, who have felt called. The purpose of the committee was to challenge that individual by asking tough questions that would make that person think deeply about his response. The committee was not just a one-night-stand. It lasted over a period of 6 weeks or so. Many times, after the discernment process was over, the person felt more sure of his calling. But other times, the person realized it was more of a personal desire than a calling. The point I’m making is that it is essential for the individual to seek confirmation of what he/she perceives as calling. It can come through the mentorship of others, through a particular passage in Scripture, or in many recognizable ways. And, it may take an extended amount of time. For instance, Abraham was 75 years old when God told him to leave Ur and promised Abraham an heir. He was 100 when Isaac was born. (Gen. 12:5; Gen.21:5)
If there are obstacles in the way, and if the calling is genuine, God will, in His time, make a path through those obstacles and will make provision. The prophet Elijah was a great example of God’s provision during the drought. (1 Ki.17,18,19)
I am reading a book called “Chasing the Wild Goose” by Mark Batterson. (The Wild Goose was a Celtic name given to the Holy Spirit–not meant to be irreverent.) In his book, Mark made an interesting statement that caught my eye. He said that many times people want to know God’s will without wanting to know God. I thought that was very insightful. So, there is another check in determining the validity of a calling…how close to God are we? How in tune with Him are we?
As to the circumstances that arise afterward, if the calling was of God, then, perhaps the apparent roadblock is as well. As was mentioned by MaryBeth @MaryBeth1, it may be that that calling was designed for that person to serve in the capacity he/she finds himself.
Paul said that “in whatsoever state I’m in, therewith to be content” (Phil. 4:11). Paul was talking about his abundance or lack of funds. He would serve God and be content with what God provided. In that case, Paul concluded that he could do all things through Christ who strengthened him. (Phil 4:13)
Then, Paul found himself with an infirmity that he pleaded with God to take away, but God didn’t for a specific reason =to keep Paul humble and for Paul to see that God’s grace was sufficient for him. So, Paul decided he would boast in his weakness because he found that when he was weak, then he was strong (2 Cor. 12:9-10).
In more recent times, Charles Spurgeon, the great revival evangelist, was known to suffer great bouts of depression throughout his life. Yet, he was used mightily by God.
So, it is not the circumstance that should cause one to doubt God’s call, but our response to it. God can use a heart that accepts his misfortune but will rely on God to allow that person to accomplish His will.
I hope this has been helpful.