Halo 3 Odst Missions Problem?

[johncena_ruckfulez]

I was completing Halo 3:Odst on Legendary(Solo).I completed about 4 to 5 missions.Then,in the middle of the 6th level,I quit because i had very low health and there were no health packs around.But I forgot to save the game.so i replayed the mission from the "missions select" option.Then, I completed the 6th mission.After that,Mombassa Streets mission came.I had to go to a particular location(i dont remember where) to search for my odst squadmate.When i checked the objectives,the earlier objectives which I completed were gone.So i went to the last objective which was left.I completed it.Then I started
Kikowani Station.I completed it.Then when i came back to Mombassa Streets,i dont get any new objective.When i go to complete the old objectives the item which i have to examine is not there.Now what should i do.When i check the guide,it says after we have completed all the objectives, a new objective is given to us.
Please Help!!!I dont want to start the campaign again on Legendary.And remember,i am playing alone.What should I do?
Help!!!
And sorry for writing such a long question.

 

[II PuRpLe ShAdOw II]

I would suggest to just continue to play the game as if nothing is wrong just do all the campaigns and when you finish it hopefully nothing is wrong and you get all your achievements.