How do I keep up with air upgrades, and ground upgrades, and infestors, and broodlords, and ultras. It seems like I'd literally need all the gas on the map lol.

Well, be clear in your mind here - there are two races that terrans are choosing from at about the 8 minute mark. Mech, and bio. Against bio, work on air upgrades and ground upgrades. Against mech, work on just ground upgrades and unit upgrades (roach speed, hydra range, chitin etc). Broodlords don't need air upgrades.
Against bio, your gas is mainly going into mutas, but since banelings are essential I like to get the necessary banelings, get research started, then dump the rest of my gas on mutas.
Against mech, spend the gas on the tech you need, then spend the leftover on roach+hydra+(viper/infestor). You'll soon hit broodlords and chitin ultras. ;)

Also, just as a side-point. Picking a strategy based on scouting info is ideal, but not always as clear in a game as it is in a replay, so, assuming inconclusive scouting intel: If a baneling all-in is working at your level, don't stop doing it because 'you don't want to rely on all-ins', like a lot of players reason. Don't bug yourself with the idea that you can't beat a terran if you don't all-in. Instead reason that a terran can't beat you unless YOU choose to let them by not busting.
You'll quickly find, if you haven't already, that the reason you're having trouble against terrans when you don't baneling all-in is because the terrans at whatever level you're currently playing at are being really, really greedy, and they're getting away with it because not enough zerg are punishing them properly. The day your busts stop working will be the day things start looking up in long-games against terran, because terrans at this level are playing fair instead of going 3cc on the back of 1 mine and 1 bunker.