Thank you for your query.
is effective only when taken on an empty stomach, so most probably the tablet you took at night would not be absorbed much if it was taken following food.
One such stray incident would not affect the baby or you or the TSH
Continue taking your eltroxin regularly as prescribed, and please do not worry.
In future, however, please be very careful about your medications and do not take them by mistake or skip them.
Go for regular 6 weekly TSH testing during pregnancy
All the best.