Why is my 5 mth old feeding every half hour, squeeling and not having many wet nappies?

Last night she wouldn't settle until midnight then she woke screaming every 1/2 - 1 hour all night and the only way to settle her was to feed. This is not normal for her as she has been sleeping all night (11pm - 8am) since 10 weeks. What could it be? She doesn't dribble as much as she used to, she seems to chew everything and I took her to the dr last week as she was playing with her ears alot he said she had a bit of a cold but that was it, a couple of days later she had a high temp in the evenings for 2 days then last night was a nightmare. I started her on solids in the middle of the day 2 weeks ago could this be it? I have checked her gums and really don't think its teething :( Could it be my milk? Should I try her on formula?