Yes, PLEASE make sure you're in the correct size. My guess is that at your height/weight you're probably in a way too big band size, too small cup size. Since 80% of your support comes from the band this means a strapless bra is going to be a miserable failure in a too big back size!
Don't fret, though, because they DO have some amazing strapless bras in smaller back/larger cup sizes. First thing you need to do is measure your underbust and your bust and report back here. Your band size=underbust measurement (more or less) but DO NOT ADD INCHES TO IT. I can't emphasize that enough. There's good research out there that adding to your underbust puts you in ill fitting bras and this is that much more important in women in D+ cups:
http://www.tandfonline.com/doi/abs/1...39.2011.647096
So start with taking your underbust=your band size and then your cup size you can estimate with this:
http://www.bralessinbrasil.com/p/fin...-that-fit.html If you have any questions about that let me know, I'm happy to help!
I do what to emphasize, though, that this is just a starting place. You need to look for signs of proper fit too in bras and there IS variation in size by brand. Look for:
- a firm band (you can only put about two fingers underneath it, not an entire hand
- the band must be parallel to the floor, if it starts to rid up, the bra is doesn't fit
- the wires should fully enclose all of your breast tissue on the sides
- the center gore should sit flat against your sternum
- your breasts must be full enclosed by the cups i.e. no quadraboob. BUT you need to make sure to put on your bras correctly to check this! Bend forward and scoop all of your breast tissue into the cups. Doing this is very, very important as it can prevent underarm fat/back fat.
Only after you nail down your correct size (and actually it will be in one brand, like I said your size by brands can vary) can you find well fitting strapless bras.
I'm not trying to scare you, it's definitely possible to find well-fitting bras. There are a lot of great places ot order online for CHEAP (around $40/bra). I have a lot of links on my website
http://www.bralessinbrasil.com/ and if you need any suggestions/help let me know!