Hi hun.
First off congrats on ur baby :)
I wouldn't worry too much if your midwife has checked you over. I am assuming she has by now. She will be keeping tabs on your weight gain and will let you know if any problems arise. I didn't put on any weight at all till I was 26 weeks pregnant and now I have shot out. If you are really worried though, you can always call your midwife and they will check you over. The number is in the front of your notes that you get at your first scan. Once you have been back for your 20 week scan they can tell alot more though, because this gives measurements and what not in alot more detail and its surprising just how fast the baby has grown. If the midwife hasnt alerted you to any problems though I wouldn't be too worried.
Pasta is always good for the weight gain and hard cheese. And my midwife told me to eat early, late and often, to put on some weight. And if u do excersise try and change it abit, so you aren't doing as much.
Hope this helps and good luck with the rest of your pregnancy.
Lauren and bump 27 weeks :) xx