Has she lost interest?

I met this girl at work a couple of weeks ago, she was really interested and was the one who initiated conversation and asked for my number rather than the other way around. We never actually work on the same days besides the one we met and we're in completely different departments so there's no issue there.

Anyway we started having conversations on whatsapp every day or two, I eventually asked her if she wanted to do something and she jumped at the chance, she seemed really excited but then a few days later I was told she remembered she had some cram classes she had to attend on the weekdays (when I'm actually free) as it's exam season and she needed the help. Fair enough I thought, she told me she may skip a couple in order to get some time but that never happened.

Anyway since that time I've kept talking to her without being pushy (once a day with occasional one or two day break after a couple), but when I do she replies pretty late despite her being online or last online for extended periods of time way after I've sent the message according to my contacts list page (I pretty much talk to most of my friends on whatsapp so I use it a lot), now I'm ok with late replies since sometimes people are just busy but when they're clearly online talking to other people it feels like kind of a slap in the face. The thing is if they were just one word or dismissive answers I'd assume she clearly lost interest and leave it at that but her responses are pretty positive and she asks stuff to keep the conversation going even if it doesn't until the next day.

Is she just not interested or am I being paranoid?

sorry to say, but i think she just lost interest man.

I think if she was really interested she would probably be writing to you a lot more and shed be very keen to arrange a date asap.

Stop talking to her and see what happens. See if she contacts you asking you out

She is probably studying with others on line......as you said she needed the help and had to attend classes. Before you pass judgement, wait till exams are over.