First, I just want to say I'm sorry you're going through this. You're in for a long process. I don't mean to sound daunting, but I also don't want to set you up for a super rosy outlook, either. Sorry this is long, but, it might help some people out:
I've assisted in a lot of personal injury work and have also experienced the process first-hand by getting in an accident that was not my fault, and having to deal with all of it when all I really wanted was to not think about it at all. Whether I worked at a law firm or not, I would have needed to hire an attorney to handle this with me (completely your choice, but I'll get into that soon). I am not a lawyer, nor do I play one on TV, so please do not take this as legal advice, but this is just my personal experience and what I've gathered as I've worked on others' cases:
First - Do NOT communicate with the other person's insurance company until you decide whether or not to obtain legal representation. Any statements you make could be used to justify lowering your settlement amount, and you'll get the runaround with communication; whereas if you get an attorney, all the communication is between your attorney and the other person's insurance, as they would no longer be allowed to contact you diretly. This is good for peace of mind to focus on what you need to focus on, aka, taking care of yourself.
Second - Go to all recommended doctors appointments, referrals, physical therapy, everything; you need to show that you are compliant with medical providers or else when the other person's insurance company requests your medical records it will appear as if your injuries weren't so bad if you didn't bother going to certain appointments or flaking out on going to physical therapy, etc.
Third - Insurance. You will have to run your medical bills through your insurance, and pay any portion of your deductible, and it will suck for a long time. It's stressful and annoying and fucks up your money situation, but it's how it works. Light at the end of the tunnel - you'll get it back. I swear some good stuff is coming up about this.
Fourth - To lawyer up or not. This is a completely personal choice, and all I can tell you is my experience. I chose to have an attorney represent me for a few reasons: I worked at a law firm and it was easy access, I didn't want to deal with getting screwed over by the other person's insurance company, and I knew if I hired an attorney, they would work to get me the best deal because the bigger the settlement amount the more they get paid. In my case, they were also able to negotiate my medical bills that had at that point turned into liens without it impacting my final settlement amount. Around my parts, personal injury cases are often settled at 3x medical costs. Many attorneys will take on personal injury cases on a 1/3 settlement fee, meaning whatever the settlement amount ends up being, 1/3 of that will go to the attorney. This leaves 1/3 for actual medical costs/liens, and 1/3 for your pocket.
Fifth - This is a timesuck. It took me 2 years to get my settlement finalized. Nothing extravagant or unique about it, just the process. Between having to show good faith efforts in non-invasive medical appointments for 8 months, finally getting the green light to get the surgery I needed 8 months earlier, the follow up appointments, the physical therapy for 4 months after surgery, getting all the billing amounts finalized (and paying for them), gathering medical records, missed wage documentation, etc. - I was so fucking over it. Depending on the nature and medical necessity of your injuries, this could be a thorn in your side for a long time. Keep track of all your medical bills, prescription costs, missed wages, history of all appointments - this will all need to be provided by you anyway, so just stay on top of it.
To me, hiring an attorney was worth it not only to negotiate the best settlement amount, but also so I could free myself emotionally and try to just focus on my well-being and recovery. Like I said, this sucked 2 years out of my life, and I felt so burned out and like I had nothing left, so I couldn't imagine having to do the negotiating my attorney had to do. I'm not sure of the extent of your injuries or if you require surgery, and I'm no help when it comes to how you should handle the time off work (at the time of my accident my employer had no benefits except PTO), but this is a shitty, shitty process and I am so sorry you have to deal with it.
Good luck on your recovery - please take care of yourself.