help gasguagedoes not work and will not take gas hardly!!!!!

[spflick]

hey there i have a 98 mercury sable dohc 24 engine and i went on vacation and i fill up when i got there and i drove 220 miles on full and then it would drop to 3/4 of a tank at 250miles and then i went to fill it up and i took four gallons and clicked off then it was like it was full but got another 10 gallons in it just pumpin slow over the time of 45 minute i finally got full. whats going on with my car why does it not fill up like it use to and my gauge ?? i have tryed different speeds on the pump handle and i have tryed moving the handle in and out nothing seems to be working. tonight it would only take four gallons total and i had about 200 miles and i know its not full. if you have any info i would greatly appreacate it if yoou could help, i dont have alot of money to play with. thanks spflick