Welcome to HCM.
Only by kissing and sucking the breast without any penetration is unlikely to cause HIV
. If that girl is a lactating women then also the chances are dim only if it happens once.
When you had started PEP? If it is started as early as possible within 24 hours of contact, then it will provide a high degree of protection fro HIV.
As you are mentioning that the test shows a faint line, it is always better to confirm with another test preferably with Western Blot test for HIV a week after the first test.