female cocker on heat, weird behaviour

Question
my female cocker spaniel has been on heat since mid-november. she has been producing a jelly-like substance that's sometimes red or yellow. websites say that the heat will last for about 3 weeks but it has been longer than that. are this liquids she's producing normal for a dog in heat and how long will they last? at times when she's out on walks, she gets into a squatting position but nothing comes out, then she will drag her rear end along the ground. is this normal? sometimes when she's out on a walk, we'll walk past a dog that she's ok with but when we walk past that dog a 2nd time, she lunges at the other dog as if she wants to attack it. she seems to only get along with female dogs. i try not to let her socialise with other dogs cos i'm afraid that she'll suddenly lunge at them.my dog is 'paper-trained' she can pee on the newspapres we set out for her but she just can't seem to do her business on the newspapers. we have tried placing her poo on the newspapers but it doesn't work. she keeps barking at anyone who walks past our house.we have tried putting coins in a can and rattling it but it doesn't effect her. she has separation anxiety.when i walk her, every few steps, she'll turn around to make sure that i'm still there. we have recently adopted her. is this 'separation anxiety' caused as i may not be her 2nd owner? she doesn't listen to commands except when there's food. she'll wait for a few seconds then carry out the command. she's a smart dog but doesn't want to listen. she has a tendency to jump on me when i appear, even if it's just for a few seconds. how do i keep her from jumping on me? she also likes to pick up socks lying on the floor and take them. what can be done to stop this? there have been some flakey things found on her. is it dried saliva, dandruff or does she have a skin problem? she likes to use her mouth to scratch herself near the place where the flakes appeared. the shampoo we use on her was recommended by the sales assistants at the shop. she is 4 yrs old. is it too late to train her? any information you can give us on how to help with the dog would be greatly appreciated=)

Answer
Lots of questions here :)

First - take her to the vet for the unproductive squatting and also get her anal glands checked.  And why hasn't she been spayed?

Now..let's do housebreaking first.  How have you been training her?
There's no reason for a 4 year old not to be housebroken in "about" a week if you get on it.  So tell me what you've been doing.

As to her general behavior - that's probably partially due to a new home and yes, a bit of anxiety.  But also a lack of training.  I'd strongly suggest some training classes.  Your local pet store will often have them - look into that.  You need to learn how to train her and most dogs enjoy the classes.  How much exercise does she get?

Skin?  Please describe these "flakey things".  Are they all over?
Just in one spot?  What shampoo are you using and are you rinsing VERY well?  Take a good look at her skin where she's at it.
Is it red?  Rashy?  Any bumps?

Delores