Australia's leading men's contender confessed to being only 80 per cent physically ready for the biggest challenge of his career after suffering a startling third-set collapse against Italian claycourter Fabio Fognini on Wednesday.
A week after retiring with stomach cramps while trailing Tommy Haas 5-2 in Halle, Tomic lost his only other grasscourt match before Wimbledon, 4-6 6-3 7-5 to Fognini at Eastbourne.
After leading 5-2 in the deciding set, Tomic dropped the last five games to the world No.61 and then admitted he was fortunate to be back on court competing at all after a week from hell at his European base in Monte Carlo.
The 19-year-old had planned a week of R & R after the French Open following a draining six-week claycourt stretch that secured his career-high ranking world No.27 heading into the grasscourt major.
Instead he fell sick, a virus leaving his Wimbledon preparation in disarray.
"I was bad for three or four days prior to Halle," Tomic told AAP.
"I was resting in Monaco where I somehow got it, so I'm lucky it went away the last few days and I'm actually feeling right to go.
"I'm back to normal, which is good, but I wouldn't say that physically I'm 100 per cent. That's why I need these few days to get ready for Monday, Tuesday.
"But I think I'm back to 80 per cent, which is good. I've got these next three days which are very, very important for next week."
Tomic described his elevation to 20th seed at the All England Club - a reward for reaching the quarter-finals last year as a qualifier - as "huge".
But he admitted having to defend the bundle of rankings points accrued from his great 2011 run was pressure of a type he'd never experienced before.
"It's tough," he said.
"But last year I won seven matches. This year I need to win four to get to the same place.
"It's good to know they announced the seedings and I got the 20th seed, which is a huge thing.
"If you make it to the third round, you eliminate playing the top eight. The most important thing for me will be to win those first two matches on grass to get maybe into the third round.
"Then I'll open up like I did last year and be more relaxed."
Tomic is entitled to use his seeding to gain practise-court privileges at the All England Club, but will try to fly under the radar at Eastbourne until Saturday instead.
"I'm going to stay here, use the gym here and keep more of a low profile," he said.
"I've got to work hard, five or six hours the next four days, to peak where I want to be next Monday or Tuesday."