I know that when people have hurt you, it's easy to retreat and trust no one. However, because it's not healthy to not even have one person you trust, it's important to try. I think it would be helpful if you found one person who you trust and build up from there. You have to have a foundation so that if you get hurt again, you can fall back into that one person's arms and get enough strength to try again. Also, talking to a professional could help because if you don't have anyone you can fully trust, they can be that person and they can also give you expert advice on how to move on from where you are.
Usually the way we try to avoid being hurt in relationships is by holding-off on trusting until we know we are safe. Trusting becomes a mechanism of protection — if the person "earns our trust" then we will gladly give it to them. And this is the problem. Because there are never any guarantees. Unfortunately guarantees are not found in relationships (computers come with guarantees — not people). And guarantees are definitely not found in our love relationships. In fact (you're not going to like this), what you probably can guarantee is that you will feel hurt sometimes by the people you love. You have to realize that trust is not about finding the perfect, trustworthy person; it's about signing up to work through hurt when it arises. If we relate to trust through this perspective then trusting becomes much easier. All of the sudden we shift from trying to avoid being hurt (which is impossible), to recognizing that we can move through anything that comes our way. This helps us feel empowered (aka a little more trusting and a little less fearful). Jump in and have faith.
Trusting people is a hard step to take after feeling hurt from them. You should take your time and make sure you fully trust them again. Everyone deserves a second chance, but it may a take a while to feel completely comfortable with giving it and that's okay.
It is not easy to trust somebody after your heart has been broken. But vulnerability is the best form of expression and it shows that you can still feel. You must ensure that you mustn't be too vulnerable but at the same time, must care for people and must trust your close ones as emotions are the best thing to have in life.