How to jump start restarting Fitness regimen after weeks of morning sickness?

Hi! I'm looking for some serious help and suggestions regarding working out and staying fit during my pregnancy. This will be my second baby and I haven't followed my regimen at all. I suffered through some terrible morning sickness for 15 weeks that made me lose weight, couldn't keep anything down for the life of me. I'm happy to say I've gotten past that, but I'm wondering is it too late to start again? Daily walks with my toddler have become a staple, but can I go back to cardio/ light weight lifting still? After I had my first baby, I went down to 175 lbs. Then I started working out and went got to150lbs! I'm 152 lbs now. My doctor and I have established my weight goal is 130 lbs. I've stopped calorie counting, but have focused on a loose Paleo type diet (I still eat bread but only toast for breakfast or with a sandwich) and I eat fruit, vegetables and meat with every meal. Since my morning sickness was so bad, eating has really become a chore for me. I guess I'm asking, is it too late in pregnancy to restart my regimen? Can I still work on toning or does that even matter because I'll be packing on more lbs? Will doing a medium walk for 20 or 30 minutes outside keep my body fit and ready for labor? I'm determined to be healthy with this baby!