Cramps

Right I don't know what's doing on, first pregnancy I'm 24+5 and I was sat in car when I started getting period like cramps in my lower stomach with bad back pain and pain in my vagina, It came on all of the sudden and it lasted about 20 mins without easing or going away, now after resting the cramps are fading away but back pain is horrible and isn't going away, is this braxton hicks or what because I don't know, I'm scared I might be going into labour but I don't know what to expect and I don't know what to do, is this just normal cramps or something more serious? I have called maternity line a few times but there's no answer and I'm sat with mixed emotions, my baby is still active and felt him today not long ago, I just don't know what this bluddy pain is