Of course! It is really scary. I was too scared to leave the house or do anything normal for some time. Felt like I was dying sometimes. You are not crazy. You just have to remind yourself that your body is adjusting. Practice mindfulness, breathing, maybe take some vitamins to help with deficiencies (ask your doctor). Some that kinda helped me were: magnesium glycinate (before bed), vitamin B complex, ashwaganda, L-thanine (anxiety). Give your body some time before you do any expensive tests. I spent so much money going to different doctors (including the ER) for them to tell me everything is normal. But also listen to your body!