Were they painful? When did they start for you?

This is my second pregnancy but I didn't really have much for contractions until like 36 weeks & they mostly felt like period cramps so I didn't even realize they were contractions for an embarrassing amount of time. I'm currently 18 weeks tomorrow & Sunday night I had real actual contractions (but only 2 over a span of about 5 minutes) that hurt so bad I woke up DH because I thought I might cry. Then last night I was having very very intense cramping all the way down my legs to my knees. It hurt to do anything & it lasted about an hour. I remember being very comfortable in the second trimester of my last pregnancy so I don't know if this is normal or not. I'm not having any bleeding or abnormal discharge & still feeling movement. I just don't know if this is normal or if I should call the doc (i have an appointment the 25th) or if I'm worrying too much or not enough. Share your experience!