Don't blame yourself for this at least ... one can go to the doctor too often, or too late, it's rarely possible to know in advance exactly when it's time to see the doctor.
In the very most cases whatever problems one have, the best, cheapest and easiest solution is to just let it go over by itself. In many cases, doctors cannot do much except offering placebo treatment. It's perfectly rational to procrastinate a visit to the doctor.
I hope you will get through those three weeks financially.