To test or not to test?

It is 3 days before my next period (on Sat) and I have been having intermittent cramps since Sunday. I usually have brown spotting before my period with the cramps but lately when I feel Im wet under and check, it's this white milky discharge.

I usually have cramps 1-2 days before my period. I dont want to keep my hopes up that I may be pregnant but it's very hard to wait! I know, even it's only 3 days! We've been TTC for about 7 months.

Is 3 days before expected period too early to test? Are there any signs/symptoms of pregnancy before your missed period?