grief is a much misunderstood concept for us Westerners, mainly because we don;t deal with death properly - we treat it something slightly shameful and to be ignored as soon as pssible.
OK - first off, all your reactions are completely normal, and in keeping with the deep loss, shock, and grief you are experiencing.
As time progresses, you will find that some days you hardly think of your friend at all, and other days, you will feel so lost in a pit of grief that you will abandon trying to climb out, and start looking around and thinking of it as home.
Grief is not an illness.You don't 'get better'. Neither is is aprocess governed by time - you will not necessarily feel bettter in six months than you do in six days - grief ebbs and flows like a tide, and you must learn to go with your feelings.
When everyone around you thinks you have 'got over it' - about six weeks is average - they will stop asking you about your feelings - and you will keep on feeling them, hard and soft, easy and impossible, and eventually, but no-one knows how long, you will assimilate your loss into the fabric of your life.
You will never 'get over' your loss, but you will learn to deal with it.
As far as your friend's husband is concerned, he will understand if you cry - it may help him to release his feelings. the 'stiff upper lip' is vastly over-rated, and he should go with his feelings as well.
This will pass ... eventually. Promise.