Hi Sir
Thanks for seeking help here.
After stopping one SSRI or SNRI abruptly , you can start another after the wash out period. Like 7 days in this case.
Most importantly this is not a clear criteria of serotonin syndrome...it's very milder version. Fever and myalgia , myoclonus are more prominent symptoms which indicates towards serotonin syndrome.
Next Steps
Relax yourself , Practice JPMR from YouTube. you will be fine soon ...