what is the best ir or cb for transition to uc

hi sorry ask a silly question but i think i am on both cb and ir esa and have been sent a migration notice, why are people asking so many questions about this ? will i be a lot worse off when i migrate if i am on both than if i was just on ir esa. i am in support group and dont understand why people say i will loose all my cb esa when i claim uc. i am worried now that i could be loosing hundreds of pounds each month, is this true and can someone put it in easy terms please as i have got to migrate in the next 6 weeks but i cant afford to be down on my money by large amounts. sorry to be a pain but i am not very clever and can not understand complicated things due to severe mental health problems, many thanks.

thank you gary , looking at my award letter i get living expenses for you and your partner, extra money because you and your partner are severely disabled, extra money because of the disability income guarantee, extra money because you are in the support group. which gives a total income-related amount of £******. can i ask 1, will i lose any of this during migration, and 2, am i on income related only or a mixture of i/r and c/b . the letter seems to say i am only on income related esa. but i am confused as you say if i get a severe disability premium i will lose it, but is the extra money because you and your partner are severely disabled what you mean by a sdp i hope not as this would make me lose £163 weekly surely that's not right. many thanks . reds123