help pleaseeeeee

so my periods are usually very regular, although they only last about 4-5 days they're on time every month, but this month my period was 4 days late n only lasted for 1 1/2 - maybe 2 days w light spotting at the end.  my boyfriend n I have been ttc for about a year n I had a miscarriage on 01/28 of this year.  I'm trying not to worry but can anyone tell me why this is happening???  could it be bad or could I maybe be pregnant again???