Okay so basically I applied to Dartmouth for early decisions November 1st, but only realised TODAY that I needed to send in two subject tests (which I have not done). My counsellor didn’t mention it, and as an international student I was very unfamiliar to the college process and assumed all colleges only required SAT reasoning tests. It’s obviously my fault for not reading the website though 
Anyways, I am scheduled to take these tests in January already. What should I do? Will Dartmouth still consider me?
January will be too late for the scores to be considered for ED. Their website is explicit about requiring them, although they do appear to have an exception for students who can’t afford to take them, Unless you meet that exception criteria, you do have a problem. One option is to change your application to regular decision.
^^ Switch to Regular Decision. Your application is incomplete and will likely not even be considered for ED.
Thanks for your replies! It was very useful. I contacted dartmouth and they said they would consider my early decison without the tests, and I am now taking them in december.
I know you have already spoken with Dartmouth but I just wanted to chime in. I applied ED as well without Subject Tests. Before I applied, I spoke with my admissions rep and he told me Dartmouth will absolutely still consider you without the subject tests. In fact, the subject tests are not relied upon as heavily as most people think, especially since you’re applying ED and they know you want to go there.