Bleeding in 2nd trimester - having a major wobble

[Gargula]

Hello,
Just want to sound off really and let all my paranoia out!
Late last week (am 19 weeks pregnant) I started having some spotting, which got worse. Went to A&E on Monday where they checked cervix (ouch!) which was closed and did a scan, which showed baby ok.
Had my anomaly scan today and baby is ok but have a partial placenta previa (sp?). Have had slight spotting since.
But I am absolutely paranoid and convinced that I am going to go into early labour as since Monday I've had a really off stomach and period like pains (mild) - which is how my first labour (a slightly premature 34 weeks) started.
I've an appointment with the MW tomorrow but am aware they are pretty helpless at this early stage to stop a miscarriage or very prem labour if it has started.
Phew, long post! Anyway - has anyone else bled in 2nd trimester and gone on to deliver a healthy baby? Or has anyone had placenta previa and been OK?
Thanks

I showed a low lying placenta at twenty week scan so was scanned again at 34 weeks and it had moved away from the cervix by itself. Think it's something to do with womb changing shape around 28 weeks (from an apple to a pear shape apparently?)and this can make the placente right itself?

My mum had spotting all the way through with my brother and he was a week late.