### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
I woke up this morning and was washing my hair and felt a knot like bump on the bottom left side of the back of my head. I have been around a lot of sick people at work and then had sick kids last week. I rarely get sick (haven t been in 4 years).I ve been nervous all day, and with any medical symptoms research done online, I ve made myself a nervous wreck. I ve seen everything from a swollen lymph node from an infection or head cold to a tumor to cancer to HIV to cyst, etc.My neck is a little stiff and a bit foggy, I ve a bit tired, but otherwise feel fine. I think I ve got myself stressed to not feeling well more so than actually really not feeling well.Should I get in or see if a head cold develops? I m scared a bit, but not really - as I tend to think it s more a swollen lymph node. I swear it wasn t there Friday and not, as of Sunday morning, I noticed it. If it s a swollen lymph node, how long do they last and am I contagious right now?

### output:

Hi, dairy have gone through your question. I can understand your concern. You may have some enlarged lymph node due to reactive hyperplasia.  Possibilities of lymphoma or cancer are less likely.  So don't worry much about that.  It may be due to infection in head and neck area.  You are not contagious with lump.  You should take a course of antibiotics.  It will disappear within a week.  If it doesn't respond to treatment then biopsy diagnosis is advisable. Consult your doctor and take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using Chat Doctor. Wish you a very good health.