ive played fallout 3 for a long dang time, and i felt that i couldnt get the full feel of the game without playing the first three fallouts. i'm trying to get through from the glow for the Brotherhood, but i dont have enough Med-x to make it. i messed up with the ghoul in The Hub, so i cant get any from his "connection".
Could i maybe get a little help from you guys?

I believe you can get some Rad-X from the Hub general store - the one with the vertically challenged shop keeper.

Rad Away helps alot as well.

Try staying close to the walls while in the Glow.

Rad X is best taken before you get close to radiation.

Also there are ways around fighting in the glow.

Doctors should have both Rad away and Rad X.

I think 3 Rad-X's are enough for the glow, maybe stock a couple Rad Aways but there is a couple in there anyway.
You can buy Rad-X from the drug dealer in Old Town, just go up to him and press the barter button.
You can also become stupid and get a free one from the guy next to Cabbot at the BOS bunker.