Now I’ve calmed down could it just be a cyst?

So I found a lump Tuesday night and instantly panicked as my mum died from breast cancer at 44. I'm only 27 so the chance are slim but still none the less crapped my self. The GP had a feel and said there was no swelling of my breast or arm pit and no puckering so she wasn't overly concerned but still referred me to the breast clinic anyway which immediately triggered me! I was a wreck yesterday but I'm trying to rationalise today and I've had a good feel and rummage at my lump today and from what I can make out I THINK it is moving a bit as I'm pushing it. Can't quite make out if it's just the skin moving over it or it is budging but I'm about 80% sure it moves. I have big boobs so I have a lot of tissue surrounding it making it difficult to really tell. It 100% has a very rubbery texture to it. It feels slightly tender but I think it's because I've been poking and prodding it so much. I'm due on my period in 2 days, if it goes down a bit after that I will feel more at ease that it's a cyst but it is looking a bit more likely it could be a cyst due to the rubbery feel and tiny bit of movement.  Did anyone else have similar and it turned out ok??