The next thing is you need to evaluate how important this friendship is to you and if it is worth it to you to make all of this extra effort. If it is an important friendship to you then let go of your concerns and pursue it. If this friendship is not all that deep and you don't feel it is that important, be free in letting it go.
Lastly, that other person may have a lot of friends that they are trying to maintain. The more friendships you have the less time you have for all of them. The other person may be busy as well and may have more time once things start to slow down a bit.
Bottom line: If this person means a lot to you, then I would recommend that you talk to them and let them know what you are feeling and let them know that they are important to you and don't give up on them. I have several friends that are extremely busy and if they know that they are important to you, they will make time for you.