Please help, any advice would help !!!): very worried

I’m new to this forum but about a week and a half ago I was in the shower and realized that I had a lump in my underarm it’s very movable and squishy like so it’s not hard and immovable! I’m 19 years old and have suffered from so much anxiety over my breast health this past year from so many things , I have not had any infections or sicknesses lately so I don’t understand if it was a lymph node why it would be swollen... what could be the cause of this ? How long should I give it before going to the doctor ? I need help please any one 

I would make an appointment to see your doctor.  Why wait. He is the only one that could relieve your anxiety.  When I first discovered a lump in my breast, I called my doctor right away.