Pregnancy symptoms

Good afternoon,
I'm new to this forum as of today.
My partner and I have been trying to conceive since the beginning of January.
Now, I've had constant lower back pain and dull menstrual cramps since last weekend. Normally, when I experience this kind of pain, I get my period on the same day. But this time, it's been going on for 4 days now, and I still haven't gotten my period.
Has anyone else experienced these symptoms at the start of pregnancy, or am I just imagining things because we really want a baby?
If there's no change by Saturday, I'll take a test.
I'm feeling quite nervous about it...

Greetings and thanks!