Rachel,
If you have a swelling in your vulva that gets worse when you stand up, that may be a varicosity. Like varicose veins on your legs, varicosities in your vulva can cause pressure and throbbing.
It's most likely though just to be swollen tissues caused by increased blood flow in general (blood volume increases by up to 50% in pregnancy). Vaginal tissues become engorged with blood, which can make some women feel a bit swollen and tender.
I think that you're more worried though that this swelling is a sign of impending labour? It's not, though I'm glad to hear you've sought advice about the bleeding. I think Grace1983 had this type of bleeding before she went into premature labour (so it's a good idea to be checked out), but many of us - including myself - have had this type of bleeding and no cause has been found. As long as baby is still moving around as normal and you have no other signs, try to relax.
It's a good idea, if you have had bleeding at any time in pregnancy, to rest as much as possible, lying on your left side if you can (this position improves blood flow to the uterus and nourishes the baby as much as possible). If I was you, I would take things easy for a few days. I know how worrying this type of bleeding is.
xx
