All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
You did not clarify to us the reason behind not praying for this long period.
In any case, we say: The prayer is the greatest pillar of Islam after the Shahaadatayn (The Two Testimonies of Faith), and a pubescent person is obliged to perform it as long as he is in sound mind.
If a person abandons it because of not believing in its obligation, then this is disbelief according to the consensus of the scholars. However, abandoning it out of laziness while believing in its obligation is a grave major sin and is the worst of all sins. In fact, many scholars are of the view that a person who abandons the prayer goes out of the fold of Islam even if he believes in its obligation.
Therefore, dear questioner, you must repent to Allah for abandoning the prayer, by regretting having abandoned it and being determined in the future to continuously observe it.
You should thank Allah Who guided you to pray before death attacks you suddenly.
If you had abandoned the prayer for this period out of laziness, then according to the view of the majority of the scholars, it is an obligation to make up the five obligatory prayers but not praying the Rawaatib supererogatory prayers. Praying the Rawaatib or other supererogatory prayers does not suffice from having to make up the obligatory ones. Rather, you must make up the obligatory prayers by making specific intentions for them.
So you make up the Thuhr prayer with the intention of making up Thuhr prayer, and you make up the ‘Asr prayer with the intention of making up the ‘Asr prayer, and so forth.
The Rawaatib and other supererogatory prayers are not sufficient and do not exempt the person for having to make up the five obligatory prayers.
You should strive every day, as much as you are able to, to make up as many obligatory prayers as possible which you had missed; do not get lazy or overburden yourself with hardship. Also, do not be negligent about your obligation of earning your livelihood. Therefore, we recommend that you, daily, make up for the prayers of two days or more, if you can.
You should not preoccupy yourself with the Rawaatib and other supererogatory prayers since you have to make up for many obligatory prayers. Rather, busy your time by making up for the obligatory prayers that are due on you.
Ad-Dassooqi from the Maaliki School of jurisprudence, said:
"It is obligatory to be moderate (observe a middle course). It is sufficient in one single day to make up (for the missed prayers) of two days or more. It is not sufficient to only make up for the prayers of one day in each day, unless one fears that, if he makes up for more than one day in one single day, then this could lead him to neglect his children (not be able to provide them with the obligatory sustenance)." [End of quote]
Allah knows best.