Contractions or something else?

FTM and I’m currently 38+4

I went for a long walk and when I got back I had so much pressure and pain in my lower abdomen, like really bad period cramps as well as pressure in my butt. It didn’t go away no matter what position I got into and it lasted a few minutes. This was like 3 hours ago and I haven’t had any pain like it since, still heaps of pressure and occasional tightening though. Was it just a random pain or the very early beginning of labour? I’m just confused because it’s seems to have been a once off so I’m not sure. Help lol