Lump in the armpit,

Hi everyone, I'm new to the forum but would like some input if possible, I discovered a lump in my armpit in middle of December, I went to my GP who examined me and he could feel the lump, because it was only a few days finding it he said give it 3 weeks if its still there he will arrange for some tests.3 weeks on my GP called to ask if the lump was still there as it was he arranged for me to be seen in the breast care clinic.at the breast care clinic I was examined by a doctor who had felt 2 different lumps, 1 in upper armpit and 2nd lower down, he said he thinks it could be a fat lump, he sent me for a mammogram who then sent me to ultra sound, I was only in there a minute or so, the lady I saw was in a hurry, didn't really ask any questions, and only asked what had I been doing with all the covid restrictions and commented when I said we had  a new puppy in the first covid-19 lick down. Then said everything was fine and I can go home. That's it.. I called the breast care team the following Tuesday (3 weeks ago) as I had found another lump on my breast on the same side, which is hard and the size of a marble, they said I should ring my GP if I have any concerns. I've been questioning weather to ring my GP or am I going to be wasting my time , and am I over reacting.. I feel like a fraud like I did when I went breast care team,and I'm over reacting. Thank you in advance.