I asked this the other day, but got little response. Just looking for some help.?

I'm 24 weeks pregnant with twins. So far (touch wood) I haven't had many problems. However over the last few weeks I've been feeling some pains low down in my uterus, almost like its contracting. I also have pelvic/groin pains (sorry to be graphic) and now I also have sharp twinges in my left leg. The leg twinges aren't sore, but occur more so when I stand up, go up stairs, get out of bed etc, same with pelvic pain. I was just wondering if anyone else has experienced this? whether your pregnant with twins or late on with a singleton pregnancy.