I have experienced something like this and here are my observations from my experience.
Firstly - well done for making it to 5 days. Keep in mind if you can make it to 5 days, you can make it to 10. If you can make it to 10 days, you can make it to a month. If you can make it to a month, you can make it to a year. So to answer your question, yes, it gets easier. But it may not be a linear progression. For me, it came in lumps. Feeling awful for the first week, really couldn’t see how it waa ever going to hurt less. Slightly better after a month. Really big improvement after six months. But ultimately healing was probably 18 months to 2 years all in all. Don’t let that figure discourage you; it certainly wasn’t as raw as the first week for all that time.
Secondly - and this may or may not apply to you, but see how it lands - when I had a very intense reaction like this (also losing a large amount of weight in a short time, terrible insomnia etc) - it was actually because my ex (as I found out later) was a dark triad personality type. Because of the way these people operate, breaking up with them literally activates the same pathway as drug withdrawal, why is why it is so mentally and physically difficult. So be kind to yourself. Sounds mad, but treat yourself like you would a child recovering from a serious illness. Because you may not even be able to feel better until time rebalances your neurotransmitters. Therapy can help here, especially if it has a somatic element.
For me, it was key to remember that I didn’t miss them - I missed who I thought they were. I would highly recommend scrubbing them from your life - delete all reminders, don’t search for them on social media etc. consider the Universe did you a favour removing this person from your life, trust it did so for a good reason, and don’t disrespect the universe by inviting them back in.
Now it is time to let your survival instinct fight back - for you and your child. I am 10 years no contact and I very rarely even think about my ex, except to thank God it didn’t work out. I couldn’t see it at the time, but I was in a dangerous place with him, and I was meant for better and brighter places ❤️ Good luck