What do contractions feel like?

[Happymama1]

So it may be weird that I'm asking this question considering this is my 3rd pregnancy.
However, in my first pregnancy I was induced and never felt my contractions until my water had to be broken and all I felt was just the strong last ones to have my son.
My second son I had last year. :( I was at 37 weeks going into my appointment the doctors told me there was no heartbeat. With and enormous pain in my heart I was taken to the hospital and induced to have a natural birth and once again had no feeling of the contractions.
Thus, my question how do you know when you start to dilate or have a contraction?

[Happymama1]

Thank you for your feedback moms.

[Cindyyee]

Tight belly, period cramps at it hardest. Strong enough your back hurts.

[Jen_Wes]

Period cramps x's 100

[Avanburen0219]

For me it starts off as a tightening feeling. I can't really feel myself dilating though. Sorry for your loss