Found a lump, terrified.

Hi everyone, just wanted to share some feelings as I'm absolutely terrified...

Last Saturday I found a very small lump in my left breast. It's moveable (I think???) but firm and painless unless I prod it too much. I went to the walk in centre on the Sunday and the nurse sent the notes to my doctor who then called me on Monday to say she'd referred me to the breast clinic. I haven't heard anything yet... it's Easter weekend so won't hear until Tuesday I guess?! 
I also have random "pains/throbs" in my arm pit/breast but I wonder if that's paranoia... I'm 35 with 2 young children and I'm just so frightened. Does anyone have any advice/helpful info?

Thank you

Julia x