In an interview with Sky Sports, Luke Shaw said: "I've a few massive regrets and I couldn't stop thinking of the mistakes that I made in the past, especially with England.
"I pulled out of a lot of camps. Around that time, I was maybe not in the best condition but I think over the last two years I've thought about it so much - that was my biggest regret.
"And yeah, of course, letting Gareth [Southgate] down. I tried to keep in touch with him just to let him know that things had changed. He's said he's picked me on merit and how I've been performing.
"The past is the past and hopefully we've forgotten about that now and can just focus on the future and I want to keep impressing him."
The Manchester United left-back added: "I think playing for your country is a massive privilege and an honour and I think at times I took advantage of that.
"I didn't really think about it too much but of course now I just want to forget the mistakes I've made in the past and Gareth's done that so we're just focusing on the future and obviously what's happening now.
"The past is the past. Let's just focus on what's happening today."
Shaw impressed on his return to the Three Lions' squad against Albania and is now primed to represent his country in the Euro 2020 this June.
