Please help

I found a lump in left breast an inch under nipple.

It feels oval and moves under my fingers although doesn't move freely around the breast.

Of course I am terrified. I am due on but it definitely feels different to that kind of tender lumps we get when we are due on. I have no other symptoms or breasts changes apart from the lump.

I thought it had shrunk but now second guessing myself.

I am waiting until after my menstrual cycle to see if it changes size.

Please someone help me, I am so scared!!!!