Low sex drive

I need some advice... I used to have a very high sex drive two years ago, but now I feel like I don't have any urge to desire sex. When I get into it , I enjoy it but is the initiative that I don't have anymore. I am 19 years old and I feel like this is the time where everyone is at their highest. My boyfriend sometimes feels frustrated because of that, since we do it about once a week and he wants more, but I prefer not to have it than to make love without desire.

I have also been dealing with a condition called Ulcerative Colitis for about 2 years and 6 months, and my medication is somewhat strong. I don't know if that can cause any difference in my sexual life but I feel like it has changed around the same time.

Please give me some recommendations if you know how to increase libido or any other comments about my situation. ❤