Hi!
If you were my patient, I would reassure you that you are going to notice things more with the second pregnancy, because you now know what they are. Because your symptoms sound a bit more severe than I would expect for 16 weeks though, I would want you to call me and I would probably want to evaluate your cervix with ultrasound to be sure it is not shortening or dilating due to the contractions.
Hope this helps!
Dr B
Considering you are only 16 weeks I would give your Dr a call just in case.