so worried! need advice!

Jhanieze
Due to health insurance issues, I have not been to the doc and i'm already 16 weeks preg from what I calculated. I bought a doppler to check the baby's heartbeat but the whole time i found out ive been hearing mine! Ive tried looking for the baby's but idk i'm just not hearing it. Thought i heard it a couple of times but it's just so faint. I rarely have preg symptoms anymore just bad headaches everyday and i'm not as hungry as much. Before, I had morning sickness, and nauseas. I do get some back aches but idk. I go to the ER on fri when my husband comes back from a work trip. I'm scared it might be a missed miscarriage. I have a lil pouch but that's it. I'm not as big as other moms around 16 weeks. Am I overreacting, worrying too much? Opinions please!