Hi... I just gave to my 6 year old choldrens nyquil for the cough and and children's Claritin (loratadine) for the runny nose. Do they interact? What should I do?

Check it out. You can use a drug interaction checker whenever you have questions about drug-drug interactions or drug - food interactions. Here is 1 option (Drugs.Com): https://www.drugs.com/drug_interactions.php Your pharmacist is also a good source of info.
Sleep inducing. Your child may be somewht sleepy. Push fluids to wash the medication out of his system.