High cholesterol 251

I'm a 30 year mom of a 5 and 3 year old. I went to get my yearly physical In Nov when I turned 30 and my cholesterol lever went up quite a bit and it was now very high 251 total levels- I was told to try and lower it with diet and exercise (my diet was awful) so I started to eat healthier and tried my best to keep a Low fat/low carb/low sugar diet. I've been going to the gym 3-5 times a weeks- i decided my health needed to come first and I actually decided 2 weeks ago that i should put my desire/ uncertainty of possibly a 3rd baby until I was in better terms with my health bc I didn't know what being pregnant would do to my numbers and I worry about heart disease since it runs in my family. Well..I waited for my period for 3 days and nothing I took a test New Year's Day and it's positive. So we are now expecting our 3rd in early September, I'm really worried this time especially since I'm not where I was with my other 2 in health. Has anyone had high cholesterol before and during pregnancy? Did you notice anything different? Any concerns? My bad cholesterol LDL is 172 , good cholesterol HDL 59.