HEADACHE/PAIN IN HEAD; HEAD FELT FLUIDY,FLOATING,FOGGY,/FREAKING OUT; FLUCTUATING LUCIDITY/FELT LUCID; PAIN IN NECK; WOKE UP AND STUMBLED; RED BLOOD (AND CLOT) WHEN BLEW NOSE; RED BLOOD (AND CLOT) WHEN BLEW NOSE; DREAMING DIZZY/DIZZY; FEELS JITTERY/NOT FEELING WELL; This spontaneous report received from a 49 year old female patient reporting on self. The patient's height, and weight were not reported. The patient's concurrent conditions included seasonal allergies. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 1808982,expiry: UNKNOWN) dose was not reported,1 total administered on 12-APR-2021 09:00 in right arm for prophylactic vaccination. No concomitant medications were reported. On an unspecified date, in the evening she had headache. On 12-APR-2021 the patient was dizzy and not feeling well at night she woke up in sleep feeling dizzy as she was dreaming dizzy, got up from bed and stumbled. She told her husband not feeling well but he tried to brush it aside.  up from bed and stumbled. She took Advil. The doctor on-call told her to calm down and to take 2 Advil and went to sleep and if it did not went away to ER. The consumer did so. On 13-APR-2021, (Tuesday morning) the consumer blew her nose and noticed red blood and clots (coming from further up higher than sinuses). She was concerned and talked to people (friends). On 14-APR-2021, around 3:00 Wednesday morning she was freaking out she called her doctor and was not available she was referred to another physician. The patient was lucid, head felt fluidy, floating and dizzy. She had pain in the head and the neck. On 15-APR-2021, Thursday morning the physician called her back and said to stop taking Advil and went to ER. Her head was heavy and fog, everything was slow and lucid. In the hospital as soon as they gave her saline IV fluid, the fog was half lifted. Laboratory data (dates unspecified) included they also did MRI and blood work which were normal. They discharged her the same day and suggested she could take Tylenol which she did Thursday night. On 16-APR-2021, Friday she felt jittery but good and will buy some Gatorade for hydration and patient also stated that both dizzy and heavy head was reduced to faint (coming down from 10 to 3.5 on a scale). The consumer suggested that the dose of the vaccine may be too much for certain individuals and suggested to reduce the dose to like half the dose or to give it in 2 shots. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from red blood (and clot) when blew nose, and stumbling on 15-APR-2021, was recovering from dizziness, fluctuating lucidity, head felt fluidy, floating, foggy,/freaking out, pain in neck, and feels jittery/not feeling well, and the outcome of headache/pain in head was not reported. This report was serious (Other Medically Important Condition).; Sender's Comments: 20210436432- covid-19 vaccine ad26.cov2.s-head felt fluidy, floating, foggy,/freaking out, red blood (and clot) when blew nose. This event(s) is considered unassessable. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s).