Mid term results

Do poor mid term results in grade 12 (62%) hamper our admission chances drastically to US universities? My teachers admit that these marks are completely deflated to demoralize us and make us perform better in the finals (which are pretty much the only thing seen for admission in my country). But this marksheet will be going to the US Universities. Are my chances all but over? I have a decent profile prior to this, both academically and extra curricular wise.