Hi L.
I'm so sorry that you're feeling so anxious right now. It does sound like you've got a lot on your plate right now. Hormones in those early months can make you feel pretty wacky about all sorts of things too.
I realize changing habits is a difficult challenge, but perhaps you can use your anxiety to your advantage. Certainly being overweight, not active and snoking are not good for you or your baby. It's always ideal if you can get yourself in the best possible shape before becoming pregnant, but getting back on track at any point makes a big difference too. So I guess my advice is to try to make a plan to make even small improvements toward a healthier lifestyle. Try to reduce your smoking and see if you can cut back to even 1 pack. As added motovation, put the money you would have spend on cigarettes into a special place each day and treat yourself to a prenatal massage or new maternity outfit or whatever you'd like after you save that money for a few weeks. Then start all over again and build another fund for another special reward just for you. Another idea is limiting where you smoke - don't let yourself smoke inside or in the car with your other children. Second-hand smoke isn't good for them either. If it's less convenient, you'll be less likely to do it as often and that money can go to your "pamper fund" and help it grow faster.
You never want to diet while pregnant, but trying to focus on eating healthy foods is great for you and baby and will help you to gain a minimal amount of weight during the pregnancy so that you don't dig yourself in deeper. Try having lots of fresh fruits or cut up veggies ready so that you can grab them easily when you feel hungry for snacks. Low-fat yogurt and cottage cheese are simple snack items too and have lots of great nutrition for you and baby without a lot of extra calories. Whole grain baked crackers or air-popped popcorn are nice and crunchy, but help you to get healthy fiber. You don't have to give up your favorite treats, but having these other healthy alternatives within easy reach may make them more appealing - both for you and your other children. Modeling healthy eating is a great way to help them to learn to do the same before they are in a position that they need to diet to reach a healthy weight.
Finding time to exercise when taking care of a family and getting motovated is hard to do. Again, try some baby steps. Every little bit you do helps. When you are out, try taking the steps instead of elevator. In these colder months, head to the mall and do some window shopping while you walk a lap around. Also, just making things less convenient for yourself can add some exercise opportunities. When going shopping, park far from the door so you have to walk a little farther. Use an upstairs bathroom instead of the first floor one during the day so you walk up and down a few extra times. While you are cooking or cleaning, try doing some squats as you work. You don't need to be at the gym and lifting weights to increase your activity level.
Perhaps making a few steps towards a healthier lifestyle will help you to feel physically better and more energetic which helps to reduce anxiety and help motovate you to keep on track. Getting started is the hardest part so don't put unrealistic expectations on yourself and don't get angry with yourself if you aren't perfect...just try again with the next opportunity. Good luck and feel free to vent whenever.
H.