I had a faint positive on a test and was 4 days late then i started my period and most of the time its 7 days was only 4days long can i be pregnent?

Trust the test : A pregnancy test can detect a bhcg of about 20. Your bhcg roughly doubles every 48 hours. Let's say the first day you took it you were barely pregnant with a level of 19. 48 hours later your bhcg would be 38 which is way above the level for a urine pregnancy test to detect it. Home tests work really well and can be trusted. Repeat and if negative then you are not pregnant.

Pregnancy: Not sure whether you are pregnant or not based on the description, but i would suggest you do another pregnancy test. If that turns out positive, then you will know. If not, then you are not pregnant. Faint positive could have been misinterpretation.