So, with that said, I was singing while playing my guitar-,.

My singing was too bad,so that I couldn't help but laugh a little.

One of my friends and I sing with a guitar, but now I think I feel really embarrassed.

About Playing The Guitar And Singing

or: "...Playing the Guitar *While* Singing"

I was've been singing along while playing my favorite songs on YouTube these days.

It should be "I've been" or "I have been" because the sentence ends with "these days", which is not used with past-tense verbs.

So, with that said, I wastried singing while playing my guitar-,.

Since we're continuing from the previous sentence, you can change "was" to "tried" to show a connection or causality from when you were singing along to music on YouTube. This is a composition correction, not a grammatical one.

My singing was toso bad, (that) I couldn't help but laugh a little.

Because of that, I end up thinking I'm good at singing by mistake.

or: "I end up mistakenly thinking I'm good at singing."

I was singing along while playing my favorite songs on YouTube these other days.

As 先日 refers to one day in the past, it gives a different meaning from "these days". "These days" means for some time recently.

So, with that saiin mind, I was singing while playing my guitar-,

"With that said" has the "but" and "however" nuance, which gives off a different meaning from intended.

Mand my singing was toso bad, I couldn't help but laugh a little.

1. "and" is added to connect with the comma ending of the previous sentence.
2. When using "too", it simply expresses the "over the top" meaning, whereas when using "so", you can continue with the effect that it caused.

When I was singing along to my favorite songs on YouTube, it sounded like I was singing pretty goodwell.

When you say "I was pretty good", you are referring to yourself rather than the singing, and "well" is more natural when describing "singing".

Because of that, I ended up mistakenly thinking I'm was good at singing by mistake.

"By mistake" refers to something you have done unintentionally (an action), whereas "mistakenly" means inaccurately or incorrectly (an idea or thought).

One of my friends and I sing with aoften sang along to the guitar, but nowwhen I think about it now, I feel really embarrassed.

When you say "I think I feel really embarrassed", it gives the impression that you may not actually feel embarrassed since it is just what you think. What you are actually thinking about is the "event" rather than "how you are feeling".

I want to focus on just playing my guitar for a while.

Adding "just" implies that you will not be singing along.

I was singing along while playing my favorite songs on YouTube these daysrecently.

“These days” would be better to use if you were speaking generally. But in this case, you’re talking about one scenario so “recently” fits better

Even I thought I sang pretty well.

So, with that said, I was singing while playing my guitar-,.

When I was singing along to my favorite songs on YouTube, it sounded like I was doing pretty good.

Because of that, I ended up thinking I'm good at singing by mistake.

One of my friends and I sing with a guitarI usually sing while playing the guitar with one of my friends, but now that I think about it, I feel really embarrassed.