I'm 5'2" and currently a small 14 (have recently lost over a stone, still a few pounds to go), big boobs, apple shaped. Whether I'm heavier or not I can wear maxi dresses or midi dresses, just not a length in between.
Some of the advice on this thread is the opposite to what I would wear. If you were previously gamine (which is something I associate with waif like proportions) you probably don't have a defined waist. Do not wear belts and it highlights this, also being short, it cuts you in two and makes you look shorter. Definitely no wrap dresses for the same reason. Sack dresses (without an added belt!) actually make me look more shapely.
I don't have slender ankles as beings short means my legs are also short. I don't wear lengths that end at the ankle. Even trousers or jeans turned up exposing the ankle make me look heavier.
My big boobs should not be highlighted with plunge necks, frills or ruffles. High necks are ok on me, particularly slash or boat necks. Slight scoops and v necks which aren't too deep are more flattering on me than deep cuts.
I favour an edgier look but achieve this mainly through accessories. Earrings, necklaces, bags, shoes and boots for example can make a huge style statement and focus is away from my lumpy bits. This is also true of hair. I focus more on making my skin look good than make up. Invest in a great perfume, if you feel good you will walk taller.
Know what suits you but don't be a slave to it. I sometimes wear a colour that isn't necessarily in my palette and it can look good if the cut and drape is right. I buy a lot in H&M which is mainly thought of as a tall and thin shop whereas I am the opposite. They do great clothes that can work on most people though and more substantial than primark. I think it's important to remember that if you're wearing something loose on the top it's better paired with something tight on the bottom half or vv.
Don't let fabric swamp you. When you are short too much volume adds pounds so choose a quite narrow a line dress over a full skirted one for example. Layers such as a structured jacket can create curves.
It's important to learn your new style. Remember when Kim Kardasian was pregnant and didn't have a clue how to dress without a defined waist? You need to move your mind set to your current shape, not how you used to be.