TL:DR; Been there. Ask yourself what it is you really want out of this struggle. If obtaining it would make it worth it and $ isn't a pressing issue, go for it.

How have you felt so far? How close do you feel, any closer in any way than when you first finished school (or whatever marked the start of your journey) looking for the next opportunity? How are your finances?

Do you still in your heart believe that this is the direction you would want to go? If you manage to obtain it before the end of the year or next year, would you look back and say to yourself, the struggle and the wait was worth it for this?

If you feel like you're going through what you're doing just because of sunk-cost, probably be a good idea to change your course. If your desire to take this path, even if it wavers a little, and the passion you had going into this journey remains, then keep going and keep trying.

I'd consider myself fortunate in the circumstances of my life, but I've been there a couple times, where as I finish the program I've been doing, the railroad track I've been following in my life seems to disappear in a dense fog of unknown, quickly approaching and it sometimes appearing like a cliff.

You never know what the future will hold, trying to predict every single possibility before deciding will only make your head spin (it did mine). What will happen will happen, but what you have control over is what you yourself would do about it. No matter what path you take, acknowledge 'possibility' but focus less on the unknown and focus more on how you can best prepare to reach your goal.