Pea sized visible lump in left breast

Hello. I have a pea sized lump in my left breast about 2 cm above my nipple. 
it's mostly painless but a bit tender when messes with (possibly in my head?) 

I can sort of move it around, almost roll it between my fingers but it does stay in place. 
 

I have an appointment at the breast clinic tomorrow. Up until now I had been fine but tonight I'm really scared. 
 

This lump has been there approximately 12 months. Due to Covid etc I thought it best not to bother anyone with it. But the GP was concerned enough to get me an appointment almost immediately. 
 

does anyone have any similar experiences? 
 

Thank you :)