What you describe happening is a mild case of ss which has passed without getting help tbh.
You have gotten better on your own.
I havent had any st john wort myself so been googling around for answers.
"The elimination half-life is somewhere between 24 and 48 hours according to one study (reference number 8 on this page), meaning that within 1 week there would be a maximum of 10% of the original amount that resulted from regular dosing. Within 2 weeks that number would drop to under 1%.Aug 22, 2015"
Elsewhere:
What are the risks of serotonin syndrome?
You could develop an electrolyte imbalance. Electrolytes are the minerals in your blood that help your nerves and muscles work properly. Your heart could be damaged from beating too fast or too slow. Your blood may not clot properly, which could lead to heavy bleeding or organ damage. Your lungs or kidneys could fail. You could have a high fever that can be life-threatening.
How can serotonin syndrome be prevented?
Ask your healthcare provider before you take any prescription or over-the-counter drugs. Tell him the names of all the medicines you take.
When should I contact my healthcare provider?
You have muscle twitching or spasms.
Your heart is racing.
You are restless or sweating for no reason.
When should I seek immediate care or call 911?
You have a seizure.
You are agitated or confused.
You are drowsy or you faint.
You are shivering or have a fever of more than 104°F (40°C).
You have fast breathing or shortness of breath.
It seems you got through the worst of it and are recovering. Theres no real harm in seeing your doctor now but the worst is over.
I wouldnt ever take st johns wort personally as it has too nany weird interactions with other drugs and would wait a few weeks before taking anything that combines with it to be sure.