Over a week late

I'm now over a week late...I took a test which came out negative though a friend of mine who is a mum of 2 was certain I was pregnant after the symptoms I had described to her.

I had spotting for one day which I expected to be my period but it never came.

I've also been feeling very nauseous and was almost vomiting this morning. There have been other things such as mild cramps and a sore lower back...and so on.

Should I wait another week or 2 and test again? Or do I see the doctor?...I'm a little lost to say the least!