She felt like she couldn't breathe; Oxygen level was low; Adrenaline rush/Felt agitated; Heart was beating fast; Blood pressure was up; This is a spontaneous report from a contactable consumer (Patient herself). A 48-year-old female patient received first dose BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Batch/Lot number: Unknown, Expiration date: Unknown) via unspecified route of administration in the right arm on 28Jan2021 13:20 as SINGLE DOSE for COVID-19 Immunization. The patients medical history included ongoing Hashimoto's disease (for about 20years), Breast cancer (had her five year clearance recently) and AFib (She had AFib two years ago because she was on too high of a dose) from an unknown date. Concomitant medications included ongoing Levothyroxine Sodium (Tirosint) at 175ug daily for hashimoto's disease and Liothyronine at 5ug daily for hashimoto's disease. Family history included her son had a reaction to a vaccine, but she is not sure which vaccine it was. His arm was swollen, red, hot, and painful after the vaccine. The patient has not tested for COVID-19 prior to vaccination and not since vaccination. The has not taken any Pfizer vaccine previously and not taken any other vaccine on the same day. The patient experienced adrenaline rush, heart was beating fast, blood pressure was up and felt agitated from 01Feb2021. She had the Pfizer vaccine on 28Jan2021 and four days later at work she felt like she had an adrenaline rush that lasted for 3 hours. It felt like her heart was beating fast, her blood pressure was up, and she felt agitated. It was unusual. It seemed to stop and she went to sleep at 20:00. She woke up at 22:00 and her heart was beating out of her chest and she felt like she couldn't breathe. Her Apple watch showed her heart was beating at 140 sitting still. She went to the hospital. It stopped after 45 minutes, maybe an hour. Her oxygen level was low when she got to the hospital. It was 92 and her blood pressure was up. She has just a higher level of agitation. She is not sure if that is the immune system. She snapped at someone at work and she has never done that. Her heart rate and blood pressure have resolved completely. The agitation is still there. She went to the ER on 02Feb2021. It resolved in the ER, so she was not admitted. She had no more racing heart that day. Her blood pressure was up in the ER. The agitation comes and goes. She gets that way when her adrenaline is going, if her blood pressure is up, or if she takes a steroid. Any kind of adrenaline reaction. She hasn't used them for so long. She did not reacting well to it. They checked her thyroid level. She had AFib two years ago because she was on too high of a dose. She was on the same brand of Tirosint, but higher dose. The dose may have been 200mg but she is not sure. She is not absolutely sure what dose she was on at that point. She wasn't on Liothyronine at that time. The patient visited the emergency room as she thought she was having a heart attack. It scared her. she is going to talk to her cardiologist to make sure it is ok for the second dose. The outcome of the events heart was beating fast and Blood pressure was up recovered, the outcome of other events was unknown.  Information on the lot/batch number has been requested.