YOU ARE ABSOLUTELY DOING THE RIGHT THING! I'm not trying to get into your personal finances...but if you have insurance I would go to an ER. Better safe than sorry. Also, if you are having pain in your back or in your kidneys that very well could be a kidney stone that you have. I do not sugarcoat anything...I will tell you the truth right up front. I know all to well about kidney stones in pregnancy because I was 9 months pregnant with 1 kidney blocked and 1 barely draining. And I drove myself to the hospital!! If it is a kidney stone you will need attention right away depending on the size of the stone. They could give you meds to help expand your Urethra so you can pass it...or they may have to do something else. That something else I do not know because unlike you I was 9 months pregnant. They enduced my labor a few days later and I had my Lithotripsy when my son was 4 days old then the other side done 1 month later.
Always go by this when you are pregnant...When in doubt, get it checked out. You will be glad you did.
If you need any other advice, I will happily help you. Because I care...and that's the truth.
Please update either the post or you can message me on what happened to you and that precious baby.