No period, not pregnant

After only having one depo shot, last August, me and my partner decided to try for our first baby I've had multiple periods since I was last due to get my shit but this month, nothing.

I followed every bit of advice on getting pregnant, all the old wives tales too, and times everything perfectly.

I was due my period last week but it never came, not even any symptoms but the test I took yesterday said negative.

I'm seeing my GP on Monday but I'm still concerned about the negative test and no period. Has anyone experienced this and have tips on not to worry too much?