missing out

In the past i have repeated the same mistakes, or similar mistakes over and over again.

Here's the pattern:
Events or relationships change in a manner or speed i am unsure about or not ready for.
I over think
I screw up
The other party (or parties depending on the scenario....i mean that in a non-dirty way) generally speaking, stop talking to me. this is usually because the hate me. And even if they dont stop speaking to me completely, the relationship changes and we're no longer 'friends'. we end up being more like 'acquaintances'.

Lately, i've been trying to not repeat this doomed cycle. i dont want this pattern to be the story of my life, so i have been taking certain steps to ensure that this wont happen.

But in doing so, have i missed out on an opportunity to have something great, or in the very least, something fun?
Am i so scared of what or who i may be in the future that i am limiting my present?