Harp strings break frequently, particularly in fall and spring when the weather changes. There is nothing wrong with your harp if you have several strings break in a short time frame. I do recommend keeping a log of string breakage. If the same string breaks repeatedly it is possible there is a burr on one of the discs or at the soundboard. 

I recommend that all harpists, even beginners, keep a spare set of strings. They should take the spare set with them anytime they move the harp for a rehearsal or performance. There is nothing more frustrating than having a string break with no replacement on hand. If you wish to lower your investment in spare strings, it is possible to have a "skeleton set" of spare strings. This would consist of all of the A, C, D, and F strings in each octave. You can use the A if a G or B breaks, and the D to replace a broken E string. 

The best video I have found for how to change a harp string is by Elizabeth Jaxon. Be sure to watch to the end of the video before changing the string, as there is good information right to the end.