Expect it today or saturday?

So i'm a little confused, in december my period was 4 days late, it started on the 29th instead of the25th. My cycles are usually 28 days exactly, so i'm wondering if i should expect it today, which there is no sign of it, or should I expect my cycle to be longer this month also? I have been having some weird symptoms this week that i've never had before like my are so tender and sore i can't even run, and i've been having heartburn for the past three days. I have never had either of those things before, not even just before a period, I've also had lower backaches and some abdominal twinges, but those things happen to me before my period. I took a test last night and it was negative, so i'm wondering can I still be pregnant with those symptoms but it's just not high enough to show on a test? Or would it definitely show on a test by the time i'm having symptoms? Also should I wait till saturday for a period? Sorry so long, I'm just kinda confused. Anyone have these kind of symptoms before getting their BFP?