Vanguard Trooper Missing 6 Or More Abilities

I recently logged in after not having played the game for a bit over a year and discovered that my Level 44 trooper is missing at least 6 of his abilities. My memory is a little hazy but from looking around on the internet I believe 4 of the abilities I lost were called; Full Auto, Sticky Grenade, Mortar Volley and Pulse Cannon. I'm also missing the ability that allows you to charge at enemies to close the distance but I can't remember what that one is called. I discovered Full Auto had been made a Commando only ability and I'm playing as a Vanguard so that explains that but I can't work out what happened to the others. I went back to my trainer and bought some abilities from him but this didn't bring back any of the missing ones. Does anyone know what may have happened or how I could get my abilities back? I could handle one or two missing abilities but so many missing has made combat so boring against regular enemies and against harder enemies I barely stand a chance. Thank you in advance for any help.