I'm not a Whole30 expert and in fact am only on Day 10 but I am a Holistic Nutritionist. Without going into a whole boatload of personal details my thoughts on reading this trail were the following:
1) Before starting the Whole30 did you have normal and regular bowel movements? (who does really, especially a mother that is breastfeeding, but it is something to think about).
2) How is your digestion? Most people these days on a (SAD) diet (not that you ate a SAD diet before just commenting on digestion in general here) do not get enough fibre and water in their diets. Most people also don't take the time to eat in a relaxed environment, we are all eating in our cars and at our desks and while doing other things. Most people don't chew their food properly. Chewing your food literally 30 times before swallowing will help you (not kidding it works) begin digesting your food more efficiently, and will force you to eat slower and eat less essentially (not that the goal is to eat less!). Bottom line is you are what you digest. You could be having trouble digestion all of your protein if you have increased it in your diet (digestive enzymes/apple cider vinegar) can help and I am sure there is likely a forum about it here. I haven't checked.
3) You need WATER, we all need water. I know if can be tough...I have a hard time drinking enough too and sometimes I find it BORING as hell! So I have gotten in the habit of filling to 32oz mason jars with water each night and I have to drink them every day. Do you check your email every morning or go on Facebook? Drink 3 glasses while doing that....BEFORE each meal have a big glass of water....not during or right after but before....it will be better for your digestion. Also if you can drink room temp water...avoid ICE cold and loads of ice cubes as this impairs your digestion as well.
4) Nightshades, eggs, nuts etc. These are all compliant and yummy foods but they can cause reactions to some people. I know myself that I am eating WAY more nightshades than I ever had in my life. Eggs are my favourite but they are a major allergen to some. Nuts and seeds are amazing and have so many amazing health benefits but if you find you are having trouble with your digestion try soaking them first. E.g. Put 2 cups of almonds in a large mason jar with filtered water and let them sit at room temperature overnight. In the morning rinse and eat...or dry them out in your oven and season them however you want...or make homemade almond milk in a snap just by adding water to them in your blender (strain them after to get the pulp out) Here is a cute video http://vimeo.com/27840577 I know that this is yet another step but if you find it works for you then you can keep them in your diet! Google soaking/sprouting chart for nuts and seeds. Some need it and others don't.
5) The only other thing I noticed and I have been guilty of this the first week of the Whole30 (without noticing) is the lack of dark leafy green and my reliance on sweet potatoes, pumpkin, carrot, beets which are all sweet vegetables. Don't get me wrong they are great and fantastic but aim to get more green on your plate....it can help with the ole' bowels. The post above where you mentioned having pain on your left side in your stomach area and your belly was full? That is your colon talking (in my humble opinion).
Don't be hard on yourself or worry about your progress....this is just the first 30 days! Good luck with everything and feel free to ask me anything! Again all of the above is my opinion and based on my own knowledge as well as practical and personal experience!