I know exactly how you feel. The key is to find some of the staples that look good on everyone-the basic t-shirts and basic cut jeans. Until you lose some weight and shape up some from exercise-I don't recommend that you wear the skin tight stuff and super low rise jeans.
I was out to dinner last night, and I saw two girls who just had babies who were wearing their "old" clothes...and they just were NOT flattering. Low rise jeans and baby tees just don't work for someone who has just had a child-because it is accentuating the exact area that is out of shape.
I have had two children myself, and it took a lot of work to get my waist back. It will happen for you, but the key is not to wear the clothing that draws attention to what you are trying to cover up.
Basic tees, boot cut jeans (they can be just below the waist style, but not "super low rise" and that sort of thing can be very flattering. Dark rinse jeans are slimming, as are darker tops like black, charcoal, and chocolate colors.