Tough times can certainly knock us off balance. The best advice I can give for this is from personal experience.. Pray through it. Let our Lord amaze you as He answers prayer and shows you how HE is with you, and HE will never leave you.
Share your testimony with others to encourage them.
Be very intentional about remembering how He has carried you through tough situations in the past.
If you're trying to stay positive and keep the faith in your own strength you'll just be disappointed and discouraged.
Trust in the Lord with all your heart, do not lean on your own understanding, in all your ways acknowledge Him, and He will direct your steps.
When you see Him working in your life through answered prayer, your faith will be strengthened.
Regarding staying positive... I just have to say this: I believe in staying positive, but you have to be careful around this. 'the world' will tell you to 'just think positive'... it's kind of a bunch of lies. I don't see anywhere in scripture where Jesus tells us to 'stay positive'. The danger is in the thought process that there is some kind of power in positive thinking. There isn't, so don't fall into that trap. It will only discourage you and cause you to lose faith. Proverbs 17:22 says:
"A joyful heart is good medicine,
but a crushed spirit dries up the bones."
Just be careful where your joy comes from.
If your joy is coming from your circumstances because everything is going well and easy in your life, you will live on a constant roller-coaster, because I promise you, more hard times will come. (John 16:33)
Don't let circumstances dictate whether it will be a good day or not. Feelings come and go as our situations change, but the LORD is our foundation who cannot be moved. HE is the same yesterday, today and forever.
Zephania 3:17 says:
17 "The Lord your God is in your midst,
a mighty one who will save;
he will rejoice over you with gladness;
he will quiet you by his love;
he will exult over you with loud singing."
Rest in the truth that HE saves, rejoices over you with gladness, quiets you by His love, and exults over you with loud singing. You are loved, you are not alone, and you will never be alone.
Drink in the truth of God's love. It's not something you need to claim or manufacture... It comes from God because that's who He is. God is love. I posted a small clip from Romans chapter 8 here, but I suggest you read the entire chapter.