I wasn't sure which group to put this under.

So I've been prescribed clexane to take throughout my pregnancy until I give Birth. Thing is I go on holiday in 5 days to Spain, I know I'm ok with my normal medication in tablet form as it was ok when we went last year. Bit I'm worried about the clexane being in a injection form. Where to I store it (hand luggage or suitcase under the plain) where do I store my sharps box and will I have a problem with coming home with it not locked as it's massive and won't be full.... Do I need a letter from for explaining medical reasons why I need to take it ect? I'm just really stressing out about it all now. I was so looking forward to my holiday until doc prescribed me this yesterday..... Any advise would be appreciated xxxx