Referral to breast clinic

Hi, I'm 39 and currently breastfeeding my third baby. During Christmastime I found a lump which I assumed to be a blocked milk duct. When it didn't go anywhere after a couple of weeks, I saw my GP who has since referred me to the breast clinic. I've been keeping myself busy (no option with my three small people around :happy:), but the appointment is tomorrow morning and over the last few days I've felt increasingly anxious and now am sick to my stomach. I just came in here to ask if anyone might know how long I might expect to be at my appointment tomorrow - my baby is still quite small and not sure how long I'll be able to leave him with my husband - he'll need feeding. I now feel a bit silly for not asking sooner. GP has said they will do initial appt, ultrasound/mammogram then biopsy and bloods. It's only just occurred to me that this might take quite a long time! Does anyone know roughly how long I might be in there? Thanks so much.