A typical match for me is I will start out with the group (strength in numbers, because I figure I suck already), acting as fire-support in my catapult. When I engage with the enemy, I feel like I'm somehow pulled ahead and it suddenly becomes 3-1, and those aren't good odds with a missile-boat mech, so I die in about 20 seconds.
When I deliberately stay back, either A) nothing happens until 5 or 6 mechs sweep through where I'm camping, or

My loadout for my catapult is 2 LRM15s with 2 small pulse lasers. Should I get rid of the small pulse lasers and add ammo for the LRMs? add more armor? Idk, which is why I'm asking you guys. I want to deal the maximum amount of damage possible, while receiving the least amount of damage possible, so I like to play lame and be a portable rocket launcher.
Another reason why I like to play lame is my framerate. I don't understand how I will go from 50+ fps when I start the match, to about 15 when the action starts. I know I can't be the only one with this problem, but my laptop (mx17r3 from alienware

Anyway, if someone could help me out with any/all of this, I'd sincerely appreciate it!