Did you double check your bmi/ ideal weight? I'm only an inch taller than you and my ideal weight is at 126. Perhaps, now that your body has had a pregnancy and especially if you're breast feeding 105 might just be underweight.
That being said I don't think 1200 calories is too little, but if you are breast feeding it might be. Try boosting it up by another 50 calories to see if that helps at all. The only other thing I can think of is your normal weekend days might be too much. While it's good to have the occasional indulgent moments try not to have more than a hundred calories more on the weekend then you do on the weekdays.
If you're 5'4 then 111lbs is actually just borderline normal weight. Anything below that and you're classed as "underweight". While you may have been a couple pounds lighter before you had your daughter, think of all the changes your body's been through since then, and maybe just let it hold onto 5lbs! You're a fully matured woman now! You do a lot of exercise too, and don't mention whether you did the same routine before pregnancy. If you didn't, then the extra 5lbs could be muscle weight. As you're already so light, I wouldn't worry about trying to lose any more. Focus on being healthy and maintaining where you're at right now. Fixating on a number that is below healthy bmi will just make you frustrated.
The Peak 8 routine it will quickly raise your heart rate 8 times for very short bursts, with a cooling down period in between. Ideally you’ll be sprinting or cycling full throttle for 30 seconds with a 90 second cool down in between each outburst.
This is the fastest way to lose fat and build muscle in the body. Peak 8 actually stimulates the growth hormone in the body. I encourage you to visit Dr Mercola’s site to learn more about Peak 8 fitness because I personally feel that it is one of the best ways to exercise, especially considering the speed at which you can lose fat and build muscle.
I highly recommend you read this article and watch the videos on the page. It will give you all the information you need to know about Peak 8 – Flood Your Body With This “Youth Hormone” In Just 20 Minutes
What you eat after Peak 8 training does matter
It’s recommended that you do not eat sugar or carbohydrate for 2 hours after the Peak 8 exercise because these foods can impact the release of the growth hormone in the body. The link is below
Figure your heart rate by this formula
The Karvonen Formula is a mathematical formula that helps you determine your target heart rate zone. The formula involves using your maximum heart rate (MHR) minus your age to come up with a target heart rate range (which is a percentage of your MHR). Staying within this range will help you work most effectively during your cardio workouts.
an example of the Karvonen formula for a 23 year old person with a resting heart rate of 65 beats per minute (*to get your resting heart rate, take your pulse for one full minute when you first wake up in the morning or after you've resting for a while). This formula also includes an updated calculation of maximum heart rate (the previous formula was 220 - age, which has now been shown to be inaccurate):
206.9 - (0.67 x 23 (age)) = 191
191 - 65 (resting heart rate) = 126
126 * 65% (low end of heart rate zone) OR 85% (high end) = 82 OR 107
82 + 65 (resting heart rate) = 147
107 + 65 (rhr) = 172
The target heart rate zone for this person would be 147 to 172
First thing in the morning before you get out of bed have a clock with a second hand and check your resting heart rate then figure your rate by the
Karvonen Formula above.
You burn 30 percent more fat from doing cardio after a weights session as opposed to cardio on its own.