Hi,
'used to' and 'would' (meaning the habit of the past) should be followed by the bare/root infinitive form of a verb(the original form of the verb).
used to/should + work
'be used to' (similar in meaning to 'be accustomed to') should be followed by the -ing form of a verb(the gerundive form).
am/are/is used to + working
'be used