I'm sexually active with my boyfriend and we are trying to conceive. My period was 5 days late this month and when it came it only lasted 3 days.. its was heavier than spotting but lighter then a regular period.could I be pregnant

While this can be a sign, normally it is not, there is just no way to tell, it can be nothing or dozens of other things causing it.

You will need to wait about 2 more weeks, then do a pregnancy test with first urine of the day

It was supposed to start on Dec 10 but didn't start until the 16th and ended on the 19th... when should I test

And normally my cycles are 23 days long this month it was 29