There are a few things you can do to get rid of these fears.
The first is to breathe deeply in and out a few times every day. When we get stressed, we forget to breathe deeply enough, and as a result our bodies are deprived of oxygen. That adds to the stress. Find a quiet place, and spend five minutes just breathing. Breathe in all the goodness that you want in your life, and breathe out all the toxins and burdens that you don't want in your life.
Don't worry about any thoughts that might plague you while you do this. Acknowledge the thoughts, but then give them a biscuit and tell them you will deal with them later because you are too busy breathing now.
The next thing is to spend time day-dreaming and focusing on what you want for yourself. Don't be shy when doing this. Dream as big as you can - and if a part of your dream then becomes real, you will still be pleased.
Also make a list every day of the things you are grateful for. Ensure that you add at least five things every day to your list.
Finally, make a list of the people you don't want back in your life, and the things you don't want to repeat. Then, for each person and situation separately, make a list of the things you learned from that person or situation about yourself. Focus on the lessons that have made you wiser and stronger, and do this until you can thank every person for their contribution to your life. Once you have done that, those people will not need to come back into your life, and you will not need them back either.
You are going to be a different person with wonderful prospects for the future within the next few weeks if you do all of the above.