I was playing NC HA with the EM6 at this point. I was also fighting a losing battle against the TR, so I was getting frustrated and probably making loads of mistakes.
I bought the EM6 during or right after beta, so it might be absolutely terrible now
EM6 is not terrible, it's just not meant for 1v1 fights. I like to put an extended mag on it and use it to put pressure on the enemy, either by sending bullets down range nonstop or by spamming a chokepoint indefinitely, daring people to walk into my line of fire. If you get 2 people with EM6's putting suppressive fire on one point nobody is going to get through.
If you're looking for a more 'competetive' LMG then most people swear by the Anchor. The GD-22S is to the Anchor as the GR-22 is to the Carnage AR, it's got a lower skill ceiling and is meant for people who aren't as skilled at shooting. As a bonus it's the cheapest LMG you can buy for NC (as far as I remember). You will notice this with most of the guns in the game, they are usually 'tiered' with two options per tier. They will typically fill the same sort of role but have stats that vary ever so slightly for them to be better suited for a different kind of player. Don't always go by the in-game stats either, research your weapon on a wiki or throughout the web (video reviews on youtube from well-known players like Wrel).
I sometimes wish there was any reason at all not to instantly quit a losing battle. You're not going to get any xp, you're not going to have any fun.
You're being farmed, being farmed is not fun (and IMO farming isn't very fun either, but PS2 revolves mostly around farming unfortunately). The best strategy is to go somewhere else, even if somewhere else is the next base in line to set up defenses or grab some armor to fight back at the base you're losing. Yesterday we were getting wiped at a base and I couldn't help but notice the skies were full of ESFs, so I went to the next base in line and grabbed my anti-air rocket launcher and just started swatting them down unopposed. You could even do the same if said base has anti-air turrets, or snipe tanks with AT guns or your engineer turret. If you had a squad or platoon at your disposal you could do this much more effectively, and may even turn the tide of the battle.
I solve my frustrations by only playing medic and not chasing kills
I think I had like ten kills over maybe an hour of playing, etc. etc. etc.
My experience is just like Miauw62's. I very rarely get kills, I just run around healing/repairing people and maybe scaring enemies with suppressing fire.
Always remember that this game is not about getting kills, but having fun. Follow the fun. If you like playing in a squad, do that. If you like to play solo, do that. If you like derping around in harassers with your friends, do that. If you like playing support as a medic or engineer, good for you. Often times my most highest scoring 'lives' are those which I don't get many kills but get an insane amount of points from other things like shield bubble.
fit out an ESF for multiple roles.
IMO ESFs shouldn't even be filling multiple roles (very well), but with the very lackluster Valkryie there isn't really much other choice for ground support than a liberator (or a battle galaxy) but then you have to rely on having another person gunning with you.