This is normal. Yes it does get easier and you will become used to single life. Eventually some man with any sense will go out with you and look after you. You will eventually get over it even if it does take some time.
I know it's one of those annoying, cliche things to say but if you feel like you need a boyfriend... you probably really shouldn't have a boyfriend. A relationship should be about the other person, wanting to be with them and no one else, not just settling... rather than just ~having a boyfriend~. Once you make that decision not to settle, you'll start to adapt and trust me, you'll be much more attractive for it. Neediness isn't cool...
Five months isn't long, especially if you've been in relationships for like five years.
It does get easier. I think most people seem to either take it badly and end up with the next person who'll have them, or they learn how to live alone. I have a friend who was clearly unhappy in her five-year relationship, eventually found the strength to end it and was unhappy and insecure for months and months afterwards. But now she's really doing well, much stronger than I've ever known her.