Replaced, Battery, Alternator, & Starter, Battery Light still comes on

In early december my alternator had gone bad and i
was stranded, had to get a new one, after that i had
a weird battery issue where the car would start,
interior lights would flash on then flicker off, all
internal electronics flickered on and off. but the
notch before you start the car allowed me to keep
the electronics on, we went and replaced the
battery. After that my car sat for about 7 hours 2
weeks later and was doing the same thing, the mext
morning it wasn’t starting or clicking, it did this
twice within another week and both times we
charged the battery externally and put it back in.
The last time the charging did not affect anything
and it made a thud and grinding noise when trying
to start. Got my starter replaced, things after this
were going well. And all the sudden i go to the store
for 15 mins, car is clicking when trying to start, wait
about 3 trys and it starts again. Last night i got it
back from sitting over night at the train station and
it took 5 trys to start. Today, starts fine, all the
interior lights come on, but after 30 seconds,
battery light comes on (-: what the hell is wrong
with my car?