Labor

Question for you ladies. What did labor feel like when it first started? I'm 31w1d I'm at work and really don't want to leave right now to go be seen if it's nothing but I'm having a terrible backache low and higher back pain.. and I'm cramping all over upper and lower stomach (period type feeling) and lots more CM.. goes from mucous looking to very watery.. the pain isn't anything i cant handle right now but it's definitely uncomfortable.. walking up and down the steps are work doesn't help either 😩 FTM so I'm not sure what to except.. TIA