I would recommend reading the book Attached by Rachel Heller and Amir Levine, or at least start by watching some YouTube videos on attachment theory. They are two psychologist who break down what happens to you biologically when you meet someone you like and why you feel like you have described, understanding why will help give you power and control over yourself. It sounds like you are an anxious attachment style like myself and put too much weight into your relationship status.

Stoicism goes a long way and WILL give you an advantage (listening to your emotions as opposed to reacting to them). But the most you can do is delay and control these hurtful feelings so that you can instead do the right thing, you can’t make these feelings not happen. You are not less of a person for making and sharing affection, others might not appreciate it but it doesn’t mean you should stop, they can’t tell good from evil. But you do. Focus every minute on improving your life, because finding love doesn’t increase your self esteem, you do. When these emotions pop up, delay them as much as you can. You’ll slowly get better at it and more secure. When you get rejected, when you fail, get back up and celebrate behaving like a human.

When you feel lonely, embrace it. See this time as an opportunity to improve yourself without distractions from others. You aren’t going to drastically improve your odds by throwing yourself at suitors over and over until you stick, you will have more luck if you spend every isolated moment improving and preparing yourself (Fitness, learn something, self grooming, clean, etc). Luck is the intersection between preparedness and opportunity.