I´m not sure Kayla, but I don´t think you can resave 72dpi pages as 300 dpi, it won´t improve the quality of your pages as they are already jpeg files. I don´t wanna be mean
but if you don´t have the psd´s I think you´ll have to do it again. My printing site software doesn´t accept less than 300dpi , talking about 12x12 pages, unless you approve the printing. And 72 dpi prints pixelated, I know it because I made home cards for my son sometimes and most cartoons I get from google come in 72 and I have to repaint them because the printing is awful. Why don´t you try and print just one sheet as a single photo, in the size you want your album, and see what it looks like, maybe then you can decide what to do.