Worried about my son

Hello,

 

Just looking a little advice or guidance from anyone who's maybe experienced the same as ourselves.

Our 7 year old son has been quiet poorly lately, always catching "viral infections", VD and we've noticed he's lost abit of weight. 
Tonight when I've went in to check on him I noticed his vein pulsating out of his neck on the right side, not alot but enough for me to notice. Then I noticed a lump just abit further behind it. It moves slightly and it's abit hard, Im unsure if I should contact my out of hours GP as our doctors aren't open again until Monday/Tuesday for the bank holiday.

 

any advice welcome