Is this caffeine poisoning and should I see a doctor?

A serving of coffee can have a different caffeine content depending on its type. If it was two teaspoons of instant coffee or coffee sprinkled from 2 flat teaspoons, then I suppose it could have been about 100 - 120 mg of caffeine, but it is difficult for me to determine exactly how much caffeine you consumed with coffee. However, it is believed that consuming up to 400 mg of caffeine per day (e.g. in the form of 4 coffees) should not cause health problems in most people. Of course, there are also individual issues - some people feel bad after just one cup, there may also be cases of hypersensitivity. Perhaps in your case the problem was caused by too short a gap between coffee and caffeine intake, but the amount of caffeine taken was greater or your individual reaction to caffeine is unusual. Caffeine overdose is said after taking more than 500 mg of caffeine per day. This amount causes strong arousal, acceleration and arrhythmia of the heart rhythm, gastric problems. It can be estimated that toxic symptoms occur after taking more than 1000 mg (1 gram), and a dose of 2000 mg (2 grams) requires hospitalization. Consuming excessive amounts of caffeine can even lead to death. Caffeine is well and quickly absorbed into the blood, reaching its maximum concentration after about 20-40 minutes. The time after which the concentration of caffeine drops by half is from 2-3 to even 9-10 hours. Ultimately, in people whose elimination time is long, caffeine may be present in the blood for quite a long time, and the persistence of adverse symptoms of its action will also depend on the dose. Although it seems that the dose of caffeine consumed by you should not lead to an overdose or poisoning, if you have disturbing symptoms all the time (in particular palpitations) - please see a doctor.