:
I love - (present simple) - we use present simple with stative verbs;
I am studying ( present continuous) - Things which are happening at the moment of speaking;
I'm sitting - (present continuous) - Definite future plans;
My lessons start ( present simple) - events which are part of a timetable;
I go ( present simple) - a regular action in present time period;
I am working (present continuous) - future plans;
I am meeting (present continuous) - future arrangements;