OP – don’t take the hard time personally. Mumsnet is generally quite a pragmatic forum and “am I pregnant” threads generally get this sort of reply.
What previous posters have said is true though, no one here can tell you if you are pregnant (especially not if a doctor couldn’t). Only a pregnancy test can do that. Unfortunately sometimes they are inconclusive for various reasons.
What was the line like on the test the doctor did, could you see it yourself?
If you are potentially 6 weeks pregnant based on LMP, then I suspect the doctor would expect a stronger line at this point, which is probably why you’ve been asked to wait a week and then test again. Either you are pregnant and hormones are taking a while to rise, in which case you should see a stronger line in a week. Or you were pregnant, but the pregnancy wasn’t viable (chemical pregnancy / early miscarriage) and your pregnancy hormones are now dropping again, in which case you would probably expect the test in a week to be negative.
Although that being said if you want to test sooner at home you can, but it sounds like it might not tell you much/reassure you, unless you see a strong definite positive.
That’s just my take on the situation, based on the information you’ve given.
Do you want to be pregnant? That isn’t clear from your posts.