I am an international student in the USA, with F-1 visa. I filed my tax return before the deadline, however, I wasn't informed that I need to submit 8843 form too attached to it. I sent it today-will I still get my tax return?

After the IRS reviews the return, they will make a decision on amending the return. You may have a penalty to pay.

I assume the OP filed Form 1040NR or 1040NR-EZ. If so, he WILL get his refund even if he did not submit the Form 8843.

In fact, he will get the refund if he filed Form 1040, 1040A or 1040EZ, even though such a return is NOT the correct return.