Can me having a std for a while when i was pregnant because i did not know i was affected cause my child to have mental health problems for my child?

I doubt it: There's a correlation between STD's and pregnancy complications (difficult delivery, early delivery) http://www.ncbi.nlm.nih.gov/pubmed/24005255 BUT Mainly it identifies people who are not taking care of themselves. These people often have other infections (toxoplasmosis, cytomegalovirus, herpes) that CAN infect the baby and CAN cause problems.

Depends on the std: Some like chlamydia and gonorrhea would not bother the fetus during pregnancy but might at delivery if untreated. Syphilis could be a problem at either time unless recognized and treated. Others (herpes) could have variable outcome,primary infection vs recurrence.