As a single parent life is pretty rough as it is, but you can't give up and hang your head. Everything in life worth having is also worth fighting for and most likely there will be some sort of fight involved with it. Just because this life is hard doesn't mean it's impossible and it also doesn't mean that you are alone on this journey.
The first thing you should look into as a single parent is staying connected to a community. There are tons of single parents all over the country who struggle day in and day out to provide for their families and stay tired because there just aren't enough hours in a day. They all share the same aggravations, failures, hardships and triumphs.
Within this community you can get advice from parents who have been there and made it through and socialize and have a relationship with people other than your children. Of course your relationship with your kids is amazing but we all need adult interaction from time to time. These people can help you make it through this tough time and be there for you when you need it most.
An important thing to remember as a single parent is to learn from your past. You may feel alone and like you want someone else there with you, but you can't jump into a relationship willy nilly without getting your own feet on the ground. You and your child's life are the most important things and if you are not in a stable situation then you shouldn't be looking for a partner just yet.
Sometimes people will jump into a relationship just so they don't have to be alone and things end up blowing up in their face. Now that you are a single parent you will need to look deeper into these situations and determine what is best for you and your child. You may decide that the person you are looking at having a relationship with is just not the best choice right now.
You must be strong for yourself and for your kid, make sure your decisions benefit both of you and you're not just making a rash decision based on your certain feelings at that moment. This is not time to be impulsive, this is time to analyze things surrounding you and making the best decision possible.