My period is late.

My period is 1 week late! I've took 2 tests and they are both negative. I don't know what to do now... Do I just wait for it to start? I've had cramps a week ago when I was supposed to start but now there is nothing. When do I take another test? I come off my injection about 8 weeks ago and I had a normal period last month. I am currently hoping to get pregnant but I've never been in this position! Please help?