Ill dog

Hi, I just wondered what you’re thoughts were on this. My jack russell cross, has been ‘sick’ for quite a while, however, we didn’t think it was very serious. For a few months, she has had a cough, well we thought it was like an attention cough, cause when you pat her gently on the back she stops. This used to only happen rarely, about once a week, now its gotten up to several times a day. In the past week or so, I’ve noticed she has a lump hear her nipples, so I told my mum, who stupidly didnt think anything of it, she just thought I was inventing problems :s In the past 2 days or so, I’ve noticed she has been walking, kind of slowly but like with a limp, as though she has fallen, and im pretty sure she hasnt, but shes walking like an old lady, but other times she can be fine. Her breathing is quite loud, not very loud, but noticable. She is only eight years old, so she hasnt reached old age yet. My mum is booking an appointment with the vet tomorrow, but I just wondred what everyone’s take on this was? I’ve read about breast cancer in dogs, and was wondering if there was a possibility of this? Thanks.