Hi..What exactly you mean by hyperactive mind is what we need to know is it the worries or constant thoughts which are bothering you.So we need to have some more details to come to a conclusion
It may not be the side effect of meditation
Next Steps
Practice sleep hygiene
Maintain regular timings of waking up
Don't take tea or coffee after lunch
Have so regular physical activity lik en exercise or yoga
Don't have dinner just before going to sleep
Use bed only to sleep not use phone or chat
Listen to some light music and do light reading just before going to bed
Don't keep looking at the time if you don't fall asleep, wait for 20 mins if you don't fall asleep get out of the bed and do some relaxing activity
Health Tips
If it doesn't get better consult a psychiatrist in person for detailed assessment and treatment