In a statement she posted on Twitter she said she felt better on Tuesday and thanked her fans for their support.
She said: "First up, I want to congratulate Ajla on an incredible performance and I’m sorry our match ended the way it did.
"I was playing the best tennis of my life in front of an amazing crowd this week and I think the whole experience caught up with me. At the end of the first set, after some super intense rallies, I started to breathe heavily and felt dizzy."
She said withdrawing was "the hardest thing in the world," but she followed the advice of her medical team when they told her to withdraw.
"I wanted to thank the people who have cheered me on every single match, I wanted to win so badly for you!" she added.
Speaking to BBC Sport, Raducanu said: "It was a combination of everything that has gone in behind the scenes in the last week and the accumulation of the excitement and the buzz and I think it's a great learning experience for me going forwards."
The teenager became the youngest British woman to make it to the second week at SW19 in the open era with a 6-3 7-5 win over world number 45 Sorana Cirstea on Saturday.
After her win, she took Wimbledon by storm and reached the last 16 and there were hopes she could claim another win against Australia’s Ajla Tomljanovic but ultimately had to withdraw.
Raducanu’s elevated profile prompted a change to the usual schedule, with the match put third on Court One instead of second.
Moving the courts prompted criticism from some after it meant Raducanu had to wait three and a half hours for her game.
'I'm sure they wanted her on late in the day for the public', Former World Number One Billie Jean King tells ITV News
There have been questions about whether the delay added to the pressure on Britain's newest tennis star.
Former World Number One, Billie Jean King told ITV News: "Professionally, it was not great for her but when we have Manic Monday that's what happens, also I'm sure they wanted her on late in the day for the public.
"Everyone would be at home watching the game and other devices - this would have made it easier."
A spokesperson for Wimbledon said: "All decisions are made with fairness and the best interests of the tournament, players, spectators and our worldwide broadcast audience at heart, but the unpredictable nature of the length of matches and the British weather can and will cause disruption to any schedule."
Raducanu finished her statement by saying: "Last night will go a long way to helping me learn what it takes to perform at the top.
"I will cherish everything we have achieved together this week and come back stronger!
"Can't wait to see what's next on my journey."
Raducanu, who is ranked 338th in the world and was handed a wild card entry to the competition, put her tennis career on hold during the coronavirus pandemic in order to concentrate on her A-Levels.She was born in Toronto in 2002 to a Chinese mother and Romanian father and the family moved over to England when she was two.
From the age of nine to when she was 16, Raducanu played at Bromley Tennis club, before moving on to train at the National Tennis Centre in Roehampton, south-west London.
John McEnroe was heavily criticised after jumping to the conclusion immediately after the match on the BBC that she could not handle the occasion.
Andy Murray weighed in, replying to a tweet from Kevin Pietersen about mental toughness being what separated good athletes from great ones, although the former England cricketer later insisted he had not been referring to Raducanu.
Murray wrote: "No question mental toughness can be what separates the best in sport but surely both of you aren’t judging her mental toughness on yesterday’s match?!
"I think some of what he (McEnroe) said was fair yes.. however the timing of it was a bit off considering nobody had any clue what her issue was injury/illness/breathings issues etc at the time of his comments."
Tracy Austin, who made her Wimbledon debut aged just 14 in 1977, said: "I think the moment just became too large.
"It was a long day. That’s a long time to think about the match. It’s very difficult to adapt to so much attention. She really has not played enough matches. It was just a bit too much to ask."