Lump but negative tests so far

Hello 

Any advice would be great. 

Today I went to the one stop clinic for a lump on my left breast. 

My mamogram was clear and she couldn't see anything on the very quick ultrasound. The nurse even said "you'll sleep well tonight" 

I then saw the surgeon who spent ages examining me then went off to talk to a colleague. I could hear bits and pieces of their discussion. The registra was saying he was worried. 
 

I've got to go back in 6 weeks to check if the lump is still there (rule out it being hormonal  - although I've been monitoring it for 2 months so don't think it is). He said he's being careful as some cancers don't show up on scans. 
 

Having now read some forum posts I think I should have asked for a biopsy today I.e the third part of the triple test. I saw my mamogram on the screen and I'm no expert (although I do have a phd in breast cancer metastasis) but they looked pretty  dense. 

Does anyone think I'll be offered a biopsy next appointment if it's still there. He did say they may scan again. should I push for it or just do what they say? 
 

Sorry for the long post I'm just a bit worried.