Hi, I don't speak from experience, but I know that the majority of people seen in the breast clinic have non-cancerous issues so please don't assume the worst. There are LOADS of reasons for lumps (anywhere in the body but ESPECIALLY in fatty areas like the breast). I do totally understand how anxiety provoking this can be though, try your hardest to actively distract yourself and do things you enjoy. Remind yourself that there are many possibilities for this lump so predicting the worst outcome is just negative thinking.
At the breast clinic, the Dr will examine your boobs and then if they feel a scan is necessary, they'll book that in. Good luck xx

I go to breast clinic for reasons other than cancer the doctors look after all breast problems like cysts, infections, problems with the milk ducts,  l was 23 on my first visit lm now retired. They run a one stop clinic so they see you and decide if you need mammogram ultrasound or both, and you have them in the clinic. You can take someone with you if you want to,  the Covid restrictions are now relaxing. You may need to wait in the corridor before being seen but they can go in with you. They can usually give you the results before you leave the clinic. .

Try to take it easy while you wait for your appointment. We all have doubts about the outcome before the visit. Talk to family if you can . I have found the breast nurses to be really nice in the clinic they are up to date with the current treatment. 
Take care 

Susie