Eating every hour! Help!

First time mommy w/a beautiful 4.5 month old baby girl and we exclusively breastfeed. Since birth she has always fed one one breast for 5-15 min and then would go approximately 2 hours before she was hungry again. When she turned 4 months things changed...we have for the last 3 weeks been eating every hour! She will eat for less time (3-5min) at a time, still on one breast, but be hungry again in an hour (sometimes only 45 min). Occasionally she will nurse on both breasts as I offer the other after she stops nursing on one side and then burp her. She is having normal wet/dirty diaper output and is steadily gaining weight so I'm not sure it's a milk issue (although I am doing lots of milk boosting smoothies/treats/supplements) I am beginning to become frustrated...I don't know know what to do but I can hardly even go out to get groceries etc because she is hungry so often. Any suggestions are appreciated.