What Test Is Best

My last period was 24th December, I normaly go between 25-27 day cycle. Today will be 27, Ive had terrible period pains but no blood atal? I have tested with the thin paper PT's ( im not sure what they called you get around 30 in a pack ) was negative, should i buy a well known brand PT or are these just as good for testing positive/negative

Thanks girls :)