Hi, I hope it's okay for me to post here, I'm 27, last week I found a very small lump in my armpit area, when I found it I brushed it off because a couple of days later I didn't think it was there anymore and I couldn't feel it, anyway I noticed two days ago that it was still there, but today It seems smaller than the last two days, I've now had it around two weeks, so I've made a doctors appointment but now I'm worried they either won't be able to find it or I'll get brushed off because of how small it is. 
has anyone else experienced lumps that seem bigger or smaller on a day to day basis? 

Im quite worried about it because I do have cancer in my family but I'm just trying to take it one step at a time.