New hire U5 question

Hello, new to the WSO forums but thought this would be a good place to get an answer to my question.

I gradated in May and started working right out of school. In September, I was let go from my job for "violating their social networking policies," after about 3 months.

When I took the job, they explained their policies (which seemed ridiculous) and I did my best to comply. They requested I delete my Facebook, linkedin, twitter, etc... Which I did, and not to associate my name with the company when it comes to posting, so that my comments could not be taken as investment advice from the company. 100% understandable.

I was then approached a few months later and they were upset that they had found comments by me on seekingalpha.com and another investment website where you invest $1,000,000 in play money. (my comments were completely harmless, mostly thanking authors for good pieces of writing, and most of them were over a year old, with a few recent ones) My comments were regarding equities, and the company name was in no way associated with my comments, and I worked for a municipal bond firm who did nothing with equities.

However, they used this as an excuse to fire me. I worked very very hard for them, came in early, worked late, never complained, and went above and beyond the requirements of my job, but the small company did not care. Their hiring/firing practices are racist/sexist/border-line illegal from what I witnessed, and I 100% did not deserve to be fired.

That is the back story.

So I tried finding a job for a few months and no one would even talk to me since I was out of work. I was desperate to get back to work... I had just graduated, moved out of my house and got an apartment right down the road from where I worked, and here I am 3 months later out of work with tons of bills.

I changed my pitch from me being out of work and fired by my previous employer, to just a still employed person seeking a new position at a new company. I simply said I was unhappy where I was and looking for a different role, and no one questioned it. Since I was "still employed there", no one called the company because that would have gotten me fired.

As soon as I did this, my resume received a lot of attention and I received a few offers.

Here is where my question comes in....

I just accepted and offer and I am set to start working for a new company in about a week. I will need to fill out new paperwork and update my U4 form at this time.

I am freaking out now because I am worried about what to put on my U4 date when it comes to when I stopped working for my previous employer.

From what I understand, when I was fired, the previous employer would have submitted a U5 with when/why I was fired. This date would be the end of september. However, the company that hired me is under the impression I was working there until November/December.

I'm really just not sure what to do or what to put. I know it is absolutely 100% terrible to lie on anything, but I HAVE TO GET BACK TO WORK. I would love any advice or insight that anyone could provide. Thanks.