Slow Crank no start. what seems to be the problem?

I have googled this the death and cant seem to find anything matching my situation.
ive had this car for about a year now (2002 Mitsubishi eclipse v6 5-speed) and after a
few months something strange happened. my car had a super sluggish time trying to
start. it would VERY slowly (this is what differs from every video i could find) try to
start but within 2-3 seconds die down and not turn over at all. kinda felt like the battery
was dead. actually the exact same symptom of a dying battery. but i gave it about 30
seconds and tried again and it start right up!! i didnt think anything of it till a few
months later it did the same thing. waiting about 30 seconds and tried again and it
worked. after that i told myself i would get it checked out but... forgot. now a few days
ago it did it again. its been about a month since it happened last. so i did what i did
before. waited about a minute and tried again. but this time it did the same thing but
worse.... waited several minutes again and now it wont even attempt to turn over. my
battery is fine. all the connectors "seem" to be fine from what i can see. but my car
feels like its dead. but when i try to start the lights only dim to about whats normal
when starting a car. so nothing out of the ordinary. what can this be??