SAHM needing motivation and tips from other SAHMs

I'm home full time with a 15 month and 4 yr old. Husband works 10-14 hour days and some Saturdays. I'm pretty much on my own with the kids. I am so stuck. 50 lbs to lose and I feel like I just don't know how to do it with the kids, trying to manage the house, shopping, cooking, appointments and play groups. All the normal SAHM stuff. I know it comes down to motivation and just doing it. I know that I should get up early and work out but I'm just so exhausted that sleeping longer, especially after maybe being up with one or both kids at night is easier. I know that I will feel better if I did. My road isn't stroller walking friendly. (I know I'm making up a lot of excuses here!). I need some inspiration and support from other moms of little kids who are in the same boat. I'll take inspiration and advice from anyone! I'm also pretty isolated here. Newish to the area, no support system or friends. Thanks, Amy