My daughter pretty much existed on milk until about 14/15 months. We started weaning at six months but she just wasn't interested at all until 10 months, and 10-14 months she pretty much only ate fruit and fish. She's 21 months now and I think would still be perfectly happy just having milk. She goes absolutely nuts when I get the milk out of the fridge! She's fine - grew normally, plenty of energy, alert, met all the milestones and so on. If you're worried give a vitamin supplement perhaps, but I think it's quite common to not want to eat when they're teething or not well.