98 firebird v6 drop in power and idles rough?

So I drove my 98 firebird about 20 miles or so and stopped and had lunch, then got back in and about 10 miles or so into my trip home the car kind of jittered and the battery gauge dropped almost all the way out and it kinda chugged (this all happend for about 4 seconds)(I also was going about 65mph, although I hit 70 on the way there with no problems) and rpms bounced around dropping pretty low. So I started to make my way to the next exit, once I got to the top of the hill for the exit I was stopped at a red and when it was idleing it felt like it was going to die, the rpms would drop (almost as if it was fighting to keep running) but this time the battery gauge was fine. Once the light turned green i gave it a little gas and it would go but it would kind of fight me to get up and going, until I got to about 3k rpm then it would run fine. Just about everytime I stopped after that it would do it again, but only almost died the one time and never the rest of the way home on back roads. Just wondering if anyone has any ideas on what the problem could be. Oh yeah I started it up in the driveway the next day and didnt seem to have an issue, kind of afraid to take it out again till I have it figured out. It was also raining kinda hard (for Washington) if that matters in any troubleshooting.